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Energy Allostasis: Uncovering The Hidden Link Between Metabolic And Mental Health
Camilla L. Nord
MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, United Kingdom

To survive, our brain must accurately predict internal states, enabling flexible, prospective regulation of the body’s physiology, or ‘allostasis’: eating before starvation, drinking before dehydration. Wide-ranging studies report a disruption in allostatic mechanisms in mental health disorders, potentially driving clinical features such as appetite dysregulation in major depression as well as known epidemiological comorbidity between depression and poor metabolic health. I will discuss a series of cognitive-computational neuroscience experiments investigating the overlap between mental and metabolic health, including finding that depression and diabetes are both associated with disruptions in effort-based decision-making, and that mental and metabolic health is associated with changes in reinforcement learning. I will situate these cognitive mechanisms in a broader model of energy allostasis as a link between disruptions to metabolism and mental health.

Central Relaxin-3/Rxfp3 Signaling Potently Drives Orexigenic Behaviors And Attenuates Cisplatin-Induced Anorexia And Body Weight Loss
Keshav S. Subramanian¹, Drew L. Belser¹, Oleksandr Orativskyi³, Ashley Lee¹, Schuylar Kamich¹, Caroline E. Geisler², Bart C. De Jonghe¹, Robert P. Doyle³, Matthew R. Hayes¹
¹University of Pennsylvania, Philadelphia , PA, United States, ²Syracuse University , Syracuse, NY, United States, ³University of Kentucky, Lexington , KY, United States, ⁴State University of New York, Upstate Medical University, Syracuse, NY, United States

The relaxin-3 system has been strongly implicated in having a role in regulating energy balance. Relaxin-3 producing neurons are found in the nucleus incertus (NI) of the brainstem and its receptor, relaxin family peptide receptor 3 (RXFP3), is widely distributed throughout the brain. Central administration of relaxin-3 potently increases food intake in rodents, while central RXFP3 antagonism blocks this effect. These findings suggest that the relaxin-3 system regulates energy balance by modulating feeding behavior, although its underlying neurobiological and physiological mechanisms remain to be determined. Here we characterize mechanisms by which relaxin-3 promotes food intake and food motivated behaviors. Central and systemic administration of relaxin-3 potently drove high-fat diet intake via increasing meal size in obese rats. Furthermore, we generated RXFP3 fl/fl Syn-Cre+ mice, which have RXFP3 knocked out neuronally, and shown that neuronal RXFP3 signaling is required for the orexigenic effects of relaxin-3. In addition, central relaxin-3 augmented food motivation for sucrose in a progressive-ratio task and hyperphagia in a binge-like eating model. We then evaluated the therapeutic potential of relaxin-3 to drive food intake in rats with cancer cachexia, a disorder characterized by metabolic disturbances, anorexia, and body weight loss,of which there are currently no effective therapeutics available. Astonishingly, pretreatment of central relaxin-3 attenuated cisplatin-induced anorexia and body weight loss. Overall, our study characterizes the neurobiological and physiological mechanisms by which the relaxin-3 system drives feeding and food-motivated behaviors and highlights its potential as a therapy for cancer cachexia and other metabolic disorders.

U-Shaped Relationship Between Exploration-Expolitation Tendencies And Consumption Of Sugar-Sweetened Beverages In Adolescent Girls
Muzayyana Akhmadjonova, Farbod Shafieian, Grace E. Shearrer
University of Wyoming, Laramie, WY, United States

How individuals learn about rewarding foods is hypothesized to underlie excess caloric consumption. We tested if differences in reward learning cognitive processes, learning from positive or negative feedback (α_gainand α_loss) and tendency to explore or exploit reward options (β), were associated with intake of sugar sweetened beverages (SSB). We expected that high exploration (low β) would be positively related to SSB intake. 36 healthy girls (age=12.5y±2.8y, body mass index percentile =58.3±33.1, SSB=105.8±121.6 gr/day) completed 12 24-hour dietary recalls over 6-months to assess SSB intake. Participants completed a novel candy reward probabilistic selection task (PST) to assess reward learning cognitive processes. Participants were presented 3 pairs of symbols with varying probabilities of an M&M or Skittle reward (AB pair: 80%, 20%; CD pair: 70%, 30%; EF pair: 60%, 40%). We fit a hierarchical Bayesian Q-learning model to PST choice data to derive learning parameters (α_gain, α_loss, β). We used Bayesian model averaging to test the association between SSB intake and α_gain, α_loss, and β,controlling for demographic covariates. We found a quadratic relationship between β and SSB intake (posterior inclusion probability =96.86, Bayes Factor (BF) =15.65). A BF between 10-30 is considered strong evidence of a relationship. The presence of an “U-shaped” quadratic relationship between SSB intake and β, the explore-exploit parameter is in line with previous work showing that an optimal cognitive function is between a low and high dopamine (DA) states. Since DA underlies explore-exploit decision making, we may be capturing a behavioral correlate of DA associated with excess caloric intake.

Texture-Dependent Variation In Inter-Bite Pauses And Their Relation To Eating Rate And Food Intake
Adeleke J Akinkurolere¹, Cody J Arvonen³, Edison Thomaz³, Walls A Theodore², Kathleen J Melanson¹
¹Department of Nutrition, University of Rhode Island, Kingston, RI, United States, ²Department of Psychology, University of Rhode Island, Kingston, RI, United States, ³Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, TX, United States

Inter-bite pauses differ across food textures, but their relevance to total food intake is uncertain. This study tested whether mean inter-bite pause duration (IBPD) predicted total food intake during a four-course meal and whether effects differed for hard (HF) versus soft foods (SF) or if they varied by chewing, sex, or BMI. Thirty adults (age=27.1±7.8y; BMI 18.3–38.9 kg/m²; 63.3% female) individually consumed a standardized laboratory lunch that was video-recorded for detailed analysis of oral-processing behaviors. Frame-by-frame coding captured bites, chews, chews-per-bite, IBPD (seconds, s), eating rate (g/min), and total meal duration (TMD, min). Foods were weighed before and after consumption to determine total food intake. IBPD was computed at the individual level for the full meal and separately for HF and SF. Hierarchical regressions, with covariates entered in a priori blocks (chews-per-bite, eating rate, TMD, sex, BMI), tested whether IBPD predicted TFI. Additional models examined texture-specific inter-bite pause effects and pause×BMI interactions. IBPD was significantly longer for SF than HF (SF=18.8s, HF=13.4s), t(29) =−5.35, p<.001. Across all models, eating rate (B≈ +11–12, ps<.001) and TMD (B≈ +11, ps<.001) were strong positive predictors of total food intake, explaining over 90% of variance (R²≈.91). IBPD, chews-per-bite, and sex did not significantly predict total food intake in any of these models, nor did pause×BMI interactions. In summary, SF produced longer IBPD than HF, but IBPD did not independently predict food intake once eating rate and TMD were controlled. Total food intake was driven by how fast and how long participants ate, not by how long they paused. IBPD is texture-sensitive, but it was not related to food intake in this context.

Circadian Analysis Of Food Intake In Rgs7Bp Knockout Mice Prone To Increased Adiposity
Paige C. Bensing¹, Shriya Singh¹, Kaitlyn Trinh¹, Diego E. Cecena¹, Kirill A. Martemyanov^2,3, Eric P. Zorrilla¹
¹Scripps Research, SAN DIEGO, CA, United States, ²University of Miami School of Medicine, Miami, FL, United States, ³UF Scripps Institute, Jupiter, FL, United States

Obesity affects ~108 million American adults; current medications require ongoing use with substantial side effects. In rodent models, we identified Rgs7bp, encoding the regulator of G protein signaling 7 binding protein, as a novel target for diet-induced obesity. RGS7BP variants associate with BMI, body weight, chronotype, and insomnia in human GWAS. Here, accordingly, we study circadian feeding in male and female Rgs7bp wildtype (WT) (n=31) and knockout (KO) (n=29) mice, which are prone to increased adiposity (by 8 weeks old, b=3.08% body fat, p<.0001). For Training Phase (15 days), adult single-housed mice free-fed on 5TUM (3.30 kcal/g; 10.4% fat; 10% fructose) via FED3 devices. For Diet Phase (8 weeks), mice then received ad lib access to: 1) 5TUM, 2) sweet-fat (SF; 4.18 kcal/g; 35% fat; 31% sucrose), or 3) intermittent SF access (24 hr, 3 d/week) with less preferred 5TUM on non-access days. Intake (1-hr bins) was individually fit to a 2-harmonic cosinor regression (R). In Training Phase, KO mice had an earlier 2nd-harmonic acrophase (p<.05) and reduced peak (p<.05). Female, but not male, KO (p=.0001) had earlier nadir times (Sex X Genotype, p<.05). In Diet Phase, KO mice had smaller 2^nd-harmonic amplitudes (p<.05), greater nadirs (p<.05), and an earlier time at nadir (p<.01) on access days. On non-access days, KO mice had smaller 2^nd-harmonic amplitudes (p<.05), smaller peaks (p<.05), and an earlier time at nadir (p<.001). Pre-existing genotype differences in body fat (%) persisted at week 8 (p<.001) and KO mice gained more body weight than WT over the study period (p<.05). Overall, KO mice show a blunted circadian rhythm of feeding with smaller amplitude caused by lower peaks and higher nadirs, which may contribute to their increased body weight and adiposity.

Dining Out In Nyc: Investigating The Influence Of Multisensory Urban Design Factors On Eating Behavior With Vr
Christina M Blackmon¹, Jose Pinto-Duarte², Rita Castro¹, Kristina Petersen¹, Yasmine Abbas³, Travis Masterson¹
¹Department of Nutrition at Pennsylvania State University, State College, PA, United States, ²Department of Architectural Engineering and Engineering Design at Pennsylvania State University, State College, PA, United States, ³Department of Arts and Architecture at Pennsylvania State University, State College, PA, United States

Premise WHO’s “Healthy Cities” initiative emphasizes the need to consider health impact when planning urban infrastructure, including restaurant design. Sensorial factors such as taste or visual aesthetics in a restaurant can influence eating behavior. Less researched, olfactory cues may also directly or indirectly alter eating behavior. Understanding the impact of smells on eating behavior could inform city regulations to support healthy habits within restaurants. Hypothesis Eating in the presence of an unpleasant smell will increase negative emotions, resulting in increased food intake and reduced mealtime when compared to a pleasant smell. Procedures 25 participants in a pilot randomized crossover trial attended two lab visits in counterbalanced order to receive the pleasant or unpleasant smell. Participants reported their mood and perception of the smell multiple times during each visit and consumed a standardized lab meal. Mean differences in mood, total food consumed, and length of meal were compared between scent conditions using paired t-tests. Linear mixed models were used to control for interacting factors. All statistics were run with SPSS. Results Although the smell conditions differed in perceived pleasantness (t=6.451, p<0.001), we did not observe a statistically significant difference in total energy of food consumed (t= -0.993, p=0.331) or length of meal (t=0.867, p=0.395) between conditions. Changes in smells also did not cause a significant change in mood (all p-values >0.05). Conclusion Current findings indicate that environmental smell alone may not be sufficient to manipulate eating behavior, but larger studies with more power to detect differences may better identify how various smell types and strengths might influence eating behavior and health.

The Role Of Calcineurin In Increasing Calcium-Permeable Ampa Receptor Recruitment In The Nucleus Accumbens.
Rowan/J Calkins, Carrie Ferrario
University of Michigan, Ann Arbor, MI, United States

External cues associated with fatty and sugary foods trigger food craving and can promote overeating that contributes to weight gain and rising obesity rates. Activity of neurons in the nucleus accumbens (NAc) play a critical role in mediating these cue-induced urges to eat. For example, activity of excitatory calcium-permeable AMPA receptors (CP-AMPARs) in the NAc is required for cue-triggered food-seeking. Consumption of a sugary, fatty junk food (JF) diet is sufficient to increase NAc CP-AMPARs and cue-triggered food seeking (unpublished observation). However, how NAc CP-AMPARs increases occur is poorly understood. Here we determined whether inhibiting the calcium-dependent protein phosphatase calcineurin (CaN), which prevents CP-AMPAR synaptic incorporation in other brain regions, is sufficient to enhance NAc CP-AMPAR transmission. We used patch-clamp electrophysiology to assess whether pretreatment with the CaN antagonist FK506 (5 μM) increases NAc core CP-AMPAR transmission in obesity-prone male rats. Initial results suggest that FK506 tends to increase CP-AMPARs as indicated by a greater ability of the CP-AMPAR antagonist Naspm (200 μM) to reduce evoked EPSC amplitude. In addition, a larger proportion of neurons in the FK506 group showed a strong Naspm sensitivity (>20% reduction) compared to controls (n = 9/18 FK506, 4/18 control cells). Ongoing studies will determine whether FK506-responsive cells are specific to D1-type or D2-type medium spiny neurons. We will also use western blotting to determine whether FK506 increases NAc CP-AMPAR phosphorylation, which mediates CP-AMPAR surface expression. These studies provide foundational information about the mechanisms that regulate NAc CP-AMPARs and will provide insights into CP-AMPAR recruitment following JF diet.

The Effects Of Amylin On The Antimicrobial Activity Of Amyloid Beta And Its Implications In Ingestive Behaviors And Alzheimer'S Disease
Tameka Clemons¹, Jada Dye¹, William Huang², Fernanda Navarro²
¹Tilman J Fertitta Family College of Medicine - University of Houston, Houston, TX, United States, ²University of Houston College of Natural Sciences, Houston, TX, United States

Rationale/Premise: Amylin is a satiety protein that is secreted from pancreatic beta cells. In addition to its normal function in satiety, dysfunctional amylin is known to contribute to the development of Type II diabetes through the formation of protein aggregates that disrupt the cell membrane and result in pancreatic beta cell dysfunction. The protein aggregates formed by amylin in pancreatic beta cells have similarities to the aggregates formed by amyloid beta in neuronal cells. Amylin and amyloid beta have both been identified as being involved in Alzheimer’s disease and having antimicrobial protein (AMP), which is significant because AMP activity may be linked to Alzheimer's disease. Hypothesis and Species: This study hypothesized that amylin acts as a regulator of Ab AMP activity in the presence of gram-positive bacteria S. epi. Procedures: S. epi was diluted to a concentration of 0.063 (McFarland standard). S. epi was mixed with amylin, Ab, or amylin + Ab. Serial dilutions were conducted. The various dilutions were streaked on an agar plate and incubated overnight. Each protein combination was tested for growth. Bacterial cells were counted on each plate and Graph Pad Prism was used for analysis. Results:The plates with S. epi + Ab demonstrated less growth than the control of S. epi. The plates with Ab and amylin together showed less growth than the control as well, corroborating with other studies showing amylin as an antimicrobial protein as well, as well as showing amylin as having an effect on Ab amp activity. Conclusion:Amylin is shown to stop the growth of gram-positive bacteria. This study suggests that amylin can increase the ability of Ab’s function, which may influence the involvement of both proteins in Alzheimer's disease.

Exendin-4-Phe1 Reduces Opioid-Mediated Behaviors And Opioid-Evoked Dopamine Levels In The Nucleus Accumbens Of Rats.
Megan C. Dalalo^1,2, Antonia Caffery^1,2, Xinming Zhang^1,2, Heath D. Schmidt^1,2
¹Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States

Given the continued prevalence of fatal overdoses associated with opioid misuse in the United States and the limitations of current FDA-approved treatments, there is an urgent need for novel pharmacotherapies to treat opioid use disorders (OUDs). Emerging studies show that glucagon-like peptide-1 receptor (GLP-1R) agonists attenuate the rewarding and reinforcing effects of addictive drugs, including opioids, in rodents and humans. Our preliminary studies indicate that Exendin-4-Phe1 (Ex-Phe1), a biased GLP-1R agonist, attenuates opioid-taking and -seeking behaviors at doses that do not produce malaise-like effects in rats. This study aims to elucidate the neurobiological mechanisms underlying the efficacy of Ex-Phe1 on opioid-mediated behaviors. We hypothesize that Ex-Phe1 will reduce opioid-evoked dopamine levels in the nucleus accumbens (NAc) of rats. Male (n=4) and female (n=1) Sprague-Dawley rats were surgically implanted with indwelling jugular catheters and injected with an adeno-associated virus expressing GRAB_DA1h, a dopamine sensor, into the NAc shell. Following a recovery period, rats were pretreated with vehicle or Ex-Phe1 (3 or 10 μg/kg, i.p.) before an acute priming injection of fentanyl (2.5 μg/kg, i.v.). GRAB_DA1h fluorescence was measured in the NAc using in vivo fiber photometry. Area under the curves (AUCs) and maximum z-scores were analyzed using one-way ANOVAs. Our pilot studies suggest that Ex-Phe1 may attenuate opioid taking, in part, by dose-dependently decreasing fentanyl-evoked dopamine levels in the ventral striatum. Future studies will optimize dosing regimens of Ex-Phe1 and assess the efficacy of GLP-1R biased agonists on drug-seeking behaviors during abstinence in opioid-experienced rats.

Effects Of A Long Lasting Gipr Agonist In Models Of Ingestive Behavior And Psychostimulant Reward
Nilay Dalvi¹, Anusha Polamarasetty¹, Sai Nikhil Reddy¹, Ethan L. Thompson¹, Aurelio Galli², Kirk Habegger³, Jeremy Day⁴, J. Andrew Hardaway¹
¹Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (UAB), Birmingham, AL, United States, ²Department of Surgery, UAB, Birmingham, AL, United States, ³Department of Medicine, UAB, Birmingham, AL, United States, ⁴Department of Neurobiology, UAB, Birmingham, AL, United States

Food and psychostimulant drugs of abuse engage overlapping neural circuits, yet their functional integration remains poorly understood. Cocaine-driven adaptations in dopamine (DA) pathways dysregulate behavior, but emerging evidence suggests that incretin-based therapeutics can modulate these same reward circuits. As a dual GLP-1R/GIPR agonist, tirzepatide highlights the potential of combined incretin signaling to influence reward-related processes. Whether GIPR agonism alone influences cocaine-associated behaviors; however, remains unknown. We hypothesized that GIPR activation using the long-acting GIPR agonist, [d-Ala²] GIP_1-42, modulates cocaine-induced reward, locomotor sensitization, and feeding. Adult male and female wildtype C57BL6/J mice underwent a conditioned place preference (CPP) protocol with either saline and cocaine (20 mg/kg) on alternating days. On the test day, mice were randomized and injected with saline or 50 μg/kg [d-Ala²] GIP_1-42 prior to chamber exploration. While both groups showed a significant preference for the cocaine-paired chamber, [d-Ala²] GIP_1-42 produced a significant decrease in the time spent in the drug-paired context. We then assessed cocaine-induced locomotor sensitization across repeated cocaine exposures and feeding using a fast-refeed paradigm. GIPR monoagonism attenuated cocaine-induced locomotor sensitization and feeding after a 24-hour fast. These findings suggest that GIPR signaling regulates psychostimulant and ingestive behaviors, potentially via modulation of DA circuits. In future studies, we will examine the impact of GIPR agonism on voluntary cocaine self-administration. Targeting GIPR may represent a novel strategy to address cocaine use disorder while simultaneously impacting energy balance and feeding dynamics.

Effects Of Calories, Sweetness And Caffeine On Metabolic Responses And Flavour Nutrient Conditioning In Humans
Yasmina Dumiaty¹, Jordan Serour¹, Martin Yeomans², Dana M Small¹
¹McGill University, Montreal, QC, Canada, ²Research Institute of the McGill University Health Center, Montreal, QC, Canada, ³University of Sussex, Brighton, United Kingdom

Sugar-sweetened beverages often contain caffeine, a stimulant that promotes dependence and increased intake. Despite frequent co-consumption, how sugar and caffeine jointly strengthen learned flavour preferences is unclear. This pilot study investigates how sugar and caffeine, alone and in combination, shape flavour preferences through perceptual, metabolic measures and fMRI. 10 participants underwent a flavour–nutrient conditioning protocol using four beverage conditions: 1) sweet/no calories (sucralose), 2) sweet/calories (sucralose+maltodextrin), 3) sweet/no calories/caffeine (sucralose+ caffeine) 4) sweet/calories/caffeine (sucralose+maltodextrin+caffeine). Each beverage was made with a distinct novel flavour and colour. At baseline, liking ratings, indirect calorimetry and blood were collected pre/post-consumption to quantify liking, energy expenditure (REE), substrate oxidation (RQ), and circulating glucose. fMRI and liking were assessed after participants consumed each beverage 5 times (over 20 days). At baseline linear mixed models revealed a shift toward carbohydrate oxidation (p = 0.0007) and increased blood glucose (p = 0.0006) after consumption of drinks containing maltodextrin. Caffeine had no influence on this effect. We also identified a main effect of time for all drinks (p = 0.0005), such that REE increased following consumption regardless of drink ingredients. Accordingly, the time * interaction comparison was not significant (p = 0.4). Conditioning had no effect on liking and neuroimaging analyses are ongoing. These results support the feasibility of our design for a larger study and suggest that 1) caffeine does not influence metabolic response to calorie ingestion and 2) sweet taste alone is sufficient to induce an increase in energy expenditure.

High-Fat-Type Gastrointestinal Microbiota Transfer Modulates Fentanyl Seeking In Mice
Santiago Galindo-Gonzalez, Jennifer M Houston, Levi Flom, Tiffini Lovell, Grayce Ross, Jordan Russelavage, Zowi Pogonat-Walters, Ana-Clara Bobadilla, Claire B de La Serre
Colorado State University, Fort Collins, CO, United States

Rewarding stimuli release dopamine (DA) from the ventral tegmental area (VTA) to the nucleus accumbens (NAc). Germ-free rodent colonization with GI content from high-fat (HF) diet animals leads to a feeding-driven DA release deficit associated with a compensatory intake increase. Here, we aim to determine if an HF-type microbiota also alters the rewarding value of fentanyl, as its consumption triggers DA release in the NAc and deficits in dopaminergic signaling are linked to opioid relapse. We manipulated male and female mice microbiota by exposing them to either HF or chow-fed animal feces (ConvHF or ConvChow), then expose them to a fentanyl conditioned place preference protocol. 16S sequencing, from fecal samples prior drug exposure, revealed that ConvHF microbiome were different from ConvChow, yet also different from HF donors. ConvHF did not develop a fentanyl-paired context preference while ConvChow did, suggesting a dysregulation in reward response in ConvHF. Fentanyl preference was negatively correlated with the abundances of some Lachnospiraceae species, which were enriched in the males ConvHF compared to males ConvChow. Separately we assessed fentanyl self-administration in ConvHF and ConvChow males. in this paradigm, mice are allowed to self-infuse fentanyl by nose-poking. Consistent with our previous results, ConvHF mice tend to self-administer less fentanyl than the controls on self-administration 5,6 and 8-12 (p values<0.01). We concluded from this data that the transfer resulted in distinct gut microbiotas in the Conv groups; Conventionalization with a HF-type microbiota appears to reduce fentanyl seeking in both paradigms tested; and some Lachnospiraceae spp. may have the capacity to alter reward behaviours.

Tirzepatide Dampens Motivation For Palatable Food With Minimal Effects On Hedonic Processing
Serena X. Gao^1,2, Alexander Bashaw^1,2, Sophia L. Fischer¹, Olivia Moody¹, Nicolas Morano¹, Ann Law¹, Lindsey A. Schier¹, Scott E. Kanoski¹, Tito Borner¹
¹Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States, ²Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, United States

The GLP-1/GIP dual analog tirzepatide is the most effective FDA-approved weight loss pharmacotherapy to date, yet the neurobehavioral mechanisms mediating its effects on food intake remain poorly understood. Here, we examined how tirzepatide influences appetitive and consummatory processes associated with palatable food. In male rats given a two-choice diet, acute systemic tirzepatide selectively reduced caloric intake from a high-fat, high-sugar (HFHS) diet without affecting chow consumption. To determine whether this reflects altered hedonic processing, a taste reactivity test was used. Analysis revealed a modest but significant shift in sucrose-evoked hedonic responses following tirzepatide treatment, characterized by fewer high-intensity tongue protrusions and an increase in lower-intensity hedonic mouth movements, without signs of aversive responses or a reduction in total hedonic responses. We then assessed effort-based motivation using an operant progressive ratio reinforcement task for HFHS pellets. Acute tirzepatide dose-dependently reduced breakpoint and active lever presses, indicating a robust decrease in motivation to work for palatable food. Finally, to assess mesolimbic dopamine dynamics during cue-driven behavior, we expressed a dopamine sensor in the nucleus accumbens medial shell and recorded dopamine binding during a Pavlovian discrimination task (CS+ predicting liquid sucrose; CS− non-reinforced). Our results revealed that tirzepatide attenuated the decline in dopamine following sucrose delivery. Collectively, these findings demonstrate that tirzepatide selectively suppresses palatable food intake primarily through reduced motivation and is associated with altered mesolimbic dopamine signaling during reward consumption.

Single-Nucleus Transcriptional And Chromatin Accessibility Profiling Of Mouse Hypothalamic Leprb Neurons Reveals Cell Type-Specific Cis-Regulatory Elements Linked To Human Obesity
Frankie/D Heyward^1,2
¹Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, United States, ²Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, United States

Rationale: Leptin receptor-expressing hypothalamic neurons (LepR^Hypo) are key regulators of energy balance, yet a comprehensive, cell type-resolved chromatin accessibility map of these neurons is lacking. Defining the cis-regulatory architecture of LepR^Hypo subtypes may reveal pathways governing body weight and candidate regulatory elements relevant to obesity. Hypothesis: Distinct LepR^Hyponeuronal subtypes exhibit unique chromatin accessibility landscapes, including conserved cis-regulatory elements linked to human obesity-related traits. Species: Mouse (Mus musculus). Number of Subjects: 6 female mice. Procedures: ~20,000 pooled LepR^Hypo nuclei were used for single-nucleus multiome (snRNA-seq/snATAC-seq). Integrated analyses identified clusters and cluster-specific open chromatin regions (OCRs). Mouse-to-human orthology mapping with obesity GWAS and eQTL integration identified conserved regulatory elements linked to obesity-related traits. Results: We identified 39 transcriptionally and epigenetically distinct clusters, including AgRP, Pomc, Foxb1, Irx5/3, Nts, PNOC, Kiss1/Pdyn, Ghrh, Tcf7l2, and Sf1/Nr5a1 populations. Three Glp1r-expressing clusters showed the highest Lepr enrichment and distinct molecular signatures. Cluster-specific OCRs delineated putative cis-regulatory elements unique to LepR^Hypo subtypes. Conserved mouse OCRs mapped near genes with high Human Genetic Evidence scores for obesity-related traits and overlapped obesity-associated GWAS loci and/or eQTLs. Conclusions/Relevance: These data provide a cell type-specific cis-regulatory atlas of LepR^Hypo neuronal subtypes and highlight conserved regulatory elements, candidate genes, and putative functional variants that may influence energy homeostasis and obesity susceptibility in humans.

Gradual Sugar Reduction Decreases Sugar Iintake Without Changing Product Liking Or Amount Eaten
Loma B Inamdar, Zata M Vickers
University of Minnesota, St Paul, MN, United States

Overconsumption of sugar, especially in sugar-sweetened beverages, is associated with health risks like obesity, diabetes, and cardiovascular disease. Our objectives were 1) determine how sugar-sweetened iced tea liking would change over time for people in a gradual reduction of sugar group compared to those in a control group, 2) determine if changes in liking ratings from the initial to the final taste test differed between the two groups, 3) determine if participants in the gradual reduction group increased their liking of lower sugar concentrations.Participants that consumed sweetened tea at least three times per week enrolled in this three-phase study: an initial taste test, a 12-week repeated consumption phase, and a final taste test. At the initial and final taste tests participants were served teas differing in sugar content. We divided participants into a control or a gradual reduction group for the 12-week repeated consumption phase by balancing the groups for their initial hedonic sensitivity to sweetness and their motivation to decrease their dietary sugar intake. The control group received a 7.7% sugar-sweetened tea for the duration of the 12 weeks. The gradual reduction group received a tea that was reduced weekly in increments of 10% of the previous week’s sucrose concentration. Over the consumption phase, liking decreased gradually and equally for the control and gradual reduction groups. From the initial taste test to the final taste test the lowest acceptable, ideal level, and the highest acceptable level of sweetness did not differ between the control and gradual reduction group.

Not All Food Is The Same: Glucagon-Like Peptide-1 Receptor Agonists Associated With Selective Reduction Of Ultraprocessed Food Reward
Jacqueline M. Katz¹, Isabelle Perraut¹, Ingrid A. Worth¹, James Henderson², Ashley N. Gearhardt¹
¹Department of Psychology, University of Michigan, Ann Arbor, MI, United States, ²Institute for Healthcare Policy and Innovation, University of Michigan, Ann Arbor, MI, United States

Glucagon-like peptide-1 receptor agonist (GLP-1RA)-based therapies have reshaped obesity and type 2 diabetes treatment. Yet research investigating their impact on food reward has largely ignored meaningful differences between ultraprocessed foods (UPFs), engineered to heighten reward salience, and minimally processed foods (MPFs). In an exploratory study, 328 human adults using semaglutide or tirzepatide for ≥3 months (74.4% women; 22-76 years) retrospectively reported pre-treatment and current food addiction (FA) symptoms (modified Yale Food Addiction Scale 2.0; 0-11), food noise (Food Noise Questionnaire; 0-20), and cravings for and enjoyment of UPFs and MPFs (0-100 visual analog scales). Data were analyzed using paired t-tests, MANOVA, and regressions with pre-post change scores. Reports of FA symptoms decreased from pre-treatment (M=4.5) to current (M=1.1), p<.001, 95%CI [3.1, 3.8]. Reductions in food noise were greater for UPFs (ΔM=7.8, baseline M=11.0) than MPFs (ΔM=0.9, baseline M=3.3), p<.001, 95%CI [6.1, 7.6] following treatment. A within-subjects 2×2 MANOVA revealed a large main effect of food type: UPF craving and enjoyment ratings decreased (ΔM= 42.1 and 38.0), whereas MPF craving and enjoyment ratings increased (ΔM=-14.3 and -15.6) following GLP-1RA initiation (p<.001, ηp²=0.60). Change was greater for cravings than enjoyment (p=.019, ηp² =0.02). In separate regressions, UPF-specific change variables (food noise, cravings, enjoyment) each significantly predicted current FA symptoms above baseline, while MPF variables did not. Findings suggest GLP-1RAs may selectively reduce UPF-related reward salience, informing how these medications reshape food reinforcement and highlighting the need for food-specific frameworks in GLP-1RA research.

Acute Effects Of Glp-1, Amylin Agonists And Their Combination On Phasic Dopamine Signaling
Mack Kroll¹, Rachel M. Donka¹, Jamie D. Roitman¹, Jon Davis², Mitchell F. Roitman¹
¹Department of Psychology, University of Illinois Chicago, Chicago, IL, United States, ²Novonordisk Research Center, Lexington , MA, United States

Dopamine has been hypothesized to promote energy intake by reinforcing eating, amplifying food seeking, and establishing learned associations with palatable food. GLP-1 receptor agonists (GLP1-RAs) administered either peripherally or centrally, attenuate food intake and measures of reinforced eating behaviors. Amylin RAs (AmyRAs) also cause weight loss and decreased motivation for food. Dual agonism results in more effective weight loss. Unknown is whether acute, systemic administration of GLP-1RAs, AmyRAs or combination affect phasic dopamine signaling – an important contributor to food reinforced behaviors. We trained ad libitum-fed rats (n=9) on a Pavlovian paradigm, where each of five different auditory cues predicted a unique frequency of stimulation to the medial forebrain bundle via a chronically implanted electrode. Fluctuations in dopamine release were measured in the nucleus accumbens core using expression of the fluorescent sensor dLight1.3b and fiber photometry. Cue and stimulation responses stabilized over 10 daily sessions. Vehicle was injected before (t-15min) session 11 and agonist (semaglutide, 10nmol/kg; cagrilintide, 10nmol/kg; combo 2nmol of each) before session 12. After 1 week, the next vehicle-agonist sessions were run. All treatments reduced 24hr body weight. Only cagrilinitide exhibited modest effects on dopamine signaling – reducing electrically- but not cue-evoked dopamine release. Results are compared to amphetamine and a kappa-opioid receptor agonist – which were effective in modulating dopamine. Taken together, these data indicate that acute, clinically relevant doses of GLP-1RAs and AmyRAs have minimal impact on phasic mesolimbic dopamine signaling, with only modest effects observed for cagrilintide on electrically evoked release.

THerapeutic Potential Of TImE-Restricted Feeding In A Mouse Model Of Triple-Negative Breast Cancer
Mary Lazzaro, Dulce Minaya, Connie Rogers, Emily Noble
University of Georgia , Athens, GA, United States

Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death among women. Triple-negative breast cancer (TNBC), the most aggressive subtype, has limited treatment options. Obesity exacerbates, and 30% calorie restriction improves outcomes in mouse models of TNBC, but this extreme calorie restriction is not easily achievable in free-living humans. Time-restricted feeding (TRF), in which the daily eating window is restricted to 8 hours, improves outcomes in TNBC, but whether this is due to reduced calorie intake, fat loss, or temporal feeding is unknown. Therefore, we hypothesized that 8-hour TRF improvements in TNBC outcomes would be attributable to reduced caloric intake. Female C57BL/6 mice (n = 64) were fed a high-fat, high-sugar (HFHS) diet for 9 weeks to induce obesity. E0771 TNBC cells (0.5 x 10⁶) were then injected into the 4th mammary fat pad. Mice were divided into four groups (n = 16 per group): ad libitum chow, ad libitum HFHS, TRF HFHS, and pair-fed (PF) HFHS, whose caloric intake was matched to the TRF group. Survivorship data were analyzed using Logrank analyses; all other data were analyzed using one- or two-way ANOVAs with Holm-Sidak post hoc analyses (P <.05 considered significant). As expected, ad libitum HFHS-fed animals had greater tumor weights compared with other groups (P = .0400). However, contrary to prior reports, TRF did not reduce calorie intake, induce weight loss, or decrease adiposity in HFHS-fed mice. We further saw no improvement in tumor volume or increased survival. These data suggest that TRF per se may not confer any benefit for TNBC outcomes when weight loss is not achieved.

Changes In Anxiety-To-Eat Distinguish Responders From Non-Responders To Nutritional Rehabilitation
Anastasiia Malykhina¹, Sarah H. Guo¹, Yanxi Liu², Angela Guarda¹, Martin A. Lindquist², Kimberly R. Smith¹
¹Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, United States, ²Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States

Individuals with anorexia nervosa (AN) often experience marked anxiety to consume foods high in energy density (HED). We previously showed that this anxiety-to-eat is portion size-dependent and improves with meal-based weight restoration treatment. Whether nutritional rehabilitation shifts this dose-response curve uniformly across patients remains unknown. Here we constructed anxiety-to-eat response curves to images of five portion sizes (0.25, 0.5, 1, 2, and 4) of HED foods collected at hospital admission and prior to discharge in inpatients with AN and atypical AN (N=22). Changes in anxiety-to-eat were analyzed using K-means clustering to identify treatment response subgroups based on patient-level response curves. Two subgroups were identified: a treatment responsive group (“responsive”, n=11; mean reduction in anxiety-to-eat = 13.0 points + 5.1 points) and a “non-responsive” group (n=11; mean reduction in anxiety-to-eat = 0.9 points + 3.2 points). The groups did not differ at baseline in eating, shape, or weight concern or eating restraint as measured by the Eating Disorder Examination Questionnaire. However, the “responsive” group had greater baseline anxiety-to-eat than the “non-responsive” group, with no between-group differences remaining after treatment. No other clinical or diagnostic variables predicted group membership or correlated with changes in anxiety-to-eat. These findings demonstrate differential responses to nutritional rehabilitation in anxiety-to-eat for HED foods and that this heterogeneity is not captured by current diagnostic or clinical measures. Anxiety-to-eat may represent a distinct clinical construct not reflected in standard admission assessments and may warrant incorporation into treatment monitoring.

Food Availability Elevates Cortisol Stress-Reactivity In Women With High Dietary Restraint
Naomi J McKay¹, Taha H Ghadeer¹, Cecelia A Redding¹, Brittany L Campanella¹, Brent P Howes¹, Lillyan P Kingsbury¹, Tamari-Rose Love¹, Kavorn F McKoy¹, A. Janet Tomiyama²
¹SUNY Buffalo State, Department of Psychology, Buffalo, NY, United States, ²University of California Los Angeles, Department of Psychology, Los Angeles, CA, United States

Eating during a laboratory stressor has not been found to reduce stress reactivity. It is possible that any anxiolytic properties of food may be specific to a subpopulation. Those high in cognitive dietary restraint are more likely to elevate energy intake in response to stress and, therefore, may be more impacted by any eating-associate anxiolytic effects. To test this, it was hypothesized that 1) food provided during anticipation of a stressor will blunt stress reactivity in women with high restraint and 2) those with high restraint will have higher energy intake in response to stress. Participants (n=87; women ages 18-30), provided baseline measures of stress (self-rated anxiety and salivary cortisol), and engaged in either the Trier Social Stress Test or a No Stress condition. Participants also were randomly assigned to have a basket of “complimentary snacks” available for 10 minutes either during stress anticipation or after the stressor. Stress measures were taken throughout, and energy intake was recorded. When anxiety was examined, there was no interaction between Stress, Restraint, and Food Timing and no main effect of Restraint. There was, however, an interaction between Stress, Restraint, and Food Timing on cortisol (F (1.76, 118.1) = 3.83, p = .03). In high restraint, access to food during stress anticipation caused an elevation in cortisol post-stress, but there was no elevation when food was only available after the stressor. Those with low restraint exhibited an opposite pattern. There was no effect of restraint on energy intake. These results suggest that access to food influences physiological stress reactivity while not impacting the emotional reaction to stress and that there are differential effects in those with low or high restraint.

Circadian Gating Of Vagal Signaling Drives Day-Night Differences In Glucose-Stimulated Insulin Secretion
Rebeca Mendez-Hernandez^1,2, Gabriel Tofani^1,2, Mingxin Yang^1,2, Lauren Woodie^2,3, Mitchell Lazar², Guillaume de Lartigue^1,2
¹Monell Chemical Senses Center, Philadelphia, PA, United States, ²University of Pennsylvania, Philadelphia, PA, United States, ³George Washington University, Washington, DC, United States

Physiological responses to feeding, including glucose metabolism, exhibit circadian rhythms. In nocturnal rodents, higher glucose tolerance coincides with the peak of food intake at the onset of the active phase, but the peripheral circuits that regulate these rhythms remain unclear. We hypothesized that vagal sensory neurons in the nodose ganglia (NG) exhibit circadian-gated responses to glucose, promoting greater glucose tolerance during the active phase. Methods: We assessed vagal glucose responses, glucose tolerance, and insulin secretion in the resting and active phases in male mice. Results: Using live calcium imaging (n=5/time) and Fos-TRAP labeling (n=7/group), we found that glucose activates NG neurons and the dorsovagal complex more strongly during the active than the resting phase. Deleting the clock gene Bmal1 in the NG abolished day-night differences in glucose tolerance by selectively reducing active-phase insulin secretion, suggesting that the local vagal clock is required for circadian glucose control (n=6/group). Ablation of CART neurons (n=6/group) impaired circadian glucose tolerance and insulin secretion, whereas selective re-expression of CART in the NG of global CART knockout mice (n=6/group) rescued both, indicating that CART signaling in the NG was necessary and sufficient for circadian glucose tolerance. Finally, one week of high-fat diet (n=6/group) abolished day-night differences in glucose tolerance, indicating that this vagal mechanism is rapidly disrupted by obesogenic feeding. Conclusion: Vagal sensory neurons act as a peripheral circadian gate for glucose-stimulated insulin secretion through a CART-dependent mechanism. Disruption of this pathway by high-fat diet may represent an early neural mechanism contributing to metabolic dysfunction

Blunting Starch Digestion Impairs Metabolic Flexibility In Mice
Edward Moncada¹, Woo-Jae Choung¹, Clay Swackhamer^1,2, Buford L. Nichols³, Anna M. R. Hayes¹
¹Department of Food Science and Technology, Oregon State University, Corvallis, OR, United States, ²Nutrition Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, United States, ³Department of Pediatrics, Agricultural Research Service, USDA, Children's Nutrition Research Center and Baylor College of Medicine, Houston, TX, United States

Dietary carbohydrate digestion plays a vital role in energy balance and metabolic health, with dysregulation contributing to conditions such as diabetes and obesity. A key component of metabolic health is metabolic flexibility, the ability to shift between carbohydrate and fat oxidation in response to substrate availability. Understanding how carbohydrate digestion and its enzymatic regulation influence substrate use may provide insights into metabolic dysfunction. We hypothesized that reduced starch digestion impairs metabolic flexibility by limiting carbohydrate oxidation and altering energy use. Thus, we examined the effects of impaired starch digestion on metabolic flexibility in maltase-glucoamylase knockout (Mgam KO; ablation of the gene for a starch-digesting glucosidase enzyme) and wild-type (WT) Sv/129 mice (N=16). WT and Mgam KO mice were fed diets containing raw corn starch (53% w/w) with or without acarbose (0.5 g/kg diet) to further blunt starch digestibility. Indirect calorimetry was conducted across two days, and a metabolic flexibility factor (MFF) was derived from RER values. Acarbose supplementation reduced carbohydrate oxidation across genotypes, resulting in lower MFF values, suggesting that reduced starch availability impairs metabolic flexibility. This effect was more pronounced in WT mice. Acarbose exposure on day 1, but not on day 2, accentuated genotype-dependent differences (p <0.05), indicating potential gut microbial adaptation over time. Acarbose also lowered energy expenditure across genotypes (p <0.05), suggesting a shift in substrate fate toward fermentation with reduced host energy yield. Overall, these findings suggest that starch digestion and its inhibition alter substrate oxidation, energy expenditure, and metabolic flexibility.

Modulation Of Dopamine Responses To Water During Progressive Rehydration
Samantha Mosher, Maxine K Loh, Mitchell F Roitman
Department of Psychology, University of Illinois Chicago, Chicago, IL, United States

Water deprivation drives water consumption, in part, by recruiting phasic mesolimbic dopamine responses to water and its cues. As animals consume water, central signals of dehydration quiesce. It remains unknown whether the dopamine response to water is diminished as animals rehydrate. Here, we tested how trial-by-trial rehydration shapes phasic dopamine responses to water. We expressed GRAB_DA3m and implanted a fiber optic in the nucleus accumbens of rats to record dopamine signaling using in vivo fiber photometry. Rats were additionally implanted with an intraoral catheter. After recovery, rats received 50 (5s, 200µL/trial or 10s, 400µL/trial) intraoral infusions of water under ad libitum access to water (ADLIB) or 24h water deprived (DEP), counterbalanced. Intraoral infusions evoked significantly more dopamine release in DEP versus ADLIB sessions. In DEP sessions, there was a significant negative slope in dopamine responses as a function of trial. Moreover, dopamine responses in RES rats decreased twice as fast in sessions with 10s trials relative to those with 5s trials. Rats react to intraoral infusions with stereotypical behavioral responses. We captured the behavioral reactivity of rats on each trial using DeepLabCut and found a close correlation between behavioral reactivity and dopamine responses. Ongoing work includes increasing groups sizes to examine sex differences. The data supports dopamine tracking the dynamic value of water during across physiological state. Dehydration amplifies initial dopamine signaling to water and the rate of rehydration modulates the decline in dopamine as homeostasis is restored. Continuous, state-dependent updating of mesolimbic dopamine during across physiological state, in turn, influences subsequent behavioral reactivity.

Cisplatin Induces A Conditioned Taste Aversion In Mice That Is Not Mitigated By Ondansetron, Elaborating On A Behavioral Model To Study Causes And Treatments Of Nausea
Vaibhavi Muranjan¹, Andrew Vallero¹, Cassandra Nguyen¹, Ginger Blonde², Ken Y. Hui¹
¹Johns Hopkins University, Baltimore, MD, United States, ²Florida State University, Tallahassee, FL, United States

Nausea is a common symptom, yet understanding of its pathogenesis and optimal treatments remains elusive, due partly to limitations in the animal models of nausea. Conditioned taste aversion (CTA) has been used in rats to demonstrate the effectiveness of nausea treatments, but few CTA studies have been conducted in mice, and none of them have assessed nausea treatments. We hypothesized that clinical nausea is closely modeled by CTA in mice, as it is in rats. Into 8-12 month old C57B6 mice (n = 83), we implanted intraoral (IO) cannulas; on subsequent consecutive days, they underwent 5 conditioning sessions, habituation, and then testing. During conditioning, 0.1% saccharin was infused IO, followed by IP administration of saline, cisplatin (0.5 or 2.5 mg/kg body weight), or lithium chloride. In each exposure group, half the mice were pre-treated with ondansetron 0.2 mg/kg IP 30 minutes before conditioning. In the testing session, behaviors during saccharin exposure were video recorded and manually scored. Compared to saline control, cisplatin conditioning at either dose decreased the proportion of taste reactivity behaviors that represented appetitive responses (P = 0.0028, U test). However, pre-treatment with ondansetron did not significantly alter this measure in any of the nausea exposure conditions. This study demonstrates, for the first time, that cisplatin elicits nausea-like behavior in mice, but pre-treatment with ondansetron does not mitigate this effect. Our findings establish the value of the CTA paradigm in the broader exploration of nausea and conditioned aversion in mice, especially in the context of transgenic approaches to elucidate relevant neural pathways; they also highlight CTA’s limitations when evaluating new and established therapies for nausea.

Sex Maturation And Bmi Differences In Neuromelanin-Sensitive Mri Among Adolescents
Afroditi Papantoni¹, Camille A. Diamond², Elianna Paninos², Jessica H. Liu^1,2, Elayna R. Seago¹, Kyle S. Burger¹
¹Monell Chemical Senses Center, Philadelphia, PA, United States, ²University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

Prior studies point to a complex relationship between dopamine (DA) and adiposity, reporting both positive and negative associations across dopaminergic brain pathways and varied levels of body weight. Recently, non-invasive imaging methods for measuring DA in the human brain have been developed, with neuromelanin-sensitive MRI (nmMRI) being used as a validated proxy for midbrain DA metabolism. Our previous work using nmMRI showed evidence of a negative quadratic relationship between DA metabolism and BMI, such as at lower BMI levels, DA was positively related to BMI, but at high BMI levels, DA had an inverse relation with BMI. Here, we used linear regression to test whether this association can be replicated in a sample of healthy-weight adolescents. Initial results from 43 adolescents (60% female, age=15±1y, BMI=20.9±2.6kg/m²) who completed a nmMRI scan show a weak positive relationship between DA metabolism in substantia nigra pars compacta (SNc) and BMI (β=0.271, p=0.063). Interestingly, biological sex was associated with significantly different DA metabolism in the SNc, with females having higher signal than males (β=1.635, p=0.005). We also observed that 69% of females vs. 0% of males had reached self-reported post pubertal period. Animal work has shown that maturation of DA neurotransmission can be impacted during adolescence by sex hormones, with these hormones exerting some of their effects through changes in midbrain DA synthesis. Adolescent hormones could have different actions on DA in males and females, distinct from those in adults. Although our results are preliminary, we report a modest replication of our previous BMI findings in adults and a new association between DA metabolism and sex maturation in the developing human brain.

Restrictive Food Parenting Practices Predict Loss-Of-Control Eating In Children With Healthy Weight, But Not In Those With Overweight/Obesity, During A Buffet-Style Test Meal
Megan E. Pierakos¹, Audrey Y. Gao², Hannah E. Kolpack¹, Lori A. Hatzinger³, Jennifer L. Temple^1,4, Katherine N. Balantekin^1,4
¹Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, United States, ²School of Nursing, University at Buffalo, Buffalo, NY, United States, ³Department of Population and Public Health Sciences, University of Southern California, Los Angeles, CA, United States, ⁴Center for Ingestive Behavior Research, University at Buffalo, Buffalo, NY, United States

Loss of control (LOC) over eating is defined as the subjective feeling of a lack of control over eating. While restrictive food parenting practices are associated with child overeating and eating in the absence of hunger, less is known about the relationship with child-reported LOC. This study aims to examine the relationship between restrictive food parenting practices and child-reported LOC eating in a buffet-style test meal. Participants include 106 children ages 8 – 11 (51% girls) and a parent. Food parenting was assessed using parent reports on the Structure and Control in Parent Feeding Questionnaire. Children completed a buffet-style test meal and reported on their LOC eating during the test meal. Child height and weight were measured and used to categorize participants as having healthy weight (HW) or overweight or obesity (OW/OB). Logistic regression models were used to examine how restriction predicted LOC after the test meal in those with 1) HW, and 2) OW/OB. Restriction positively predicted reported LOC eating during the test meal in children with HW (p =.041), but not in children with OW/OB (p = .649). There is a well-established link between parental restriction and disordered eating behaviors, so the results in children with HW are unsurprising. However, the results in children with OW/OB indicate that parental restriction has no impact on reported LOC eating at the test meal. These data suggest that children with OW/OB may be less sensitive to parental restriction or that LOC eating is related to other unstudied factors. Future research should assess other potential triggers of LOC eating in children with OW/OB.

A Gliotransmitter Target For Metabolic Disease: Octadecaneuropeptide Alters Systemic Nutrient Utilization And Amino Acid Metabolism
Destiny Regalia¹, Michaela Murphy¹, Matt Morris², Caroline Geisler¹
¹University of Kentucky, Lexington, KY, United States, ²University of Kansas, Lawrence, KS, United States

Octadecaneuropeptide (ODN) is a post-prandially recruited gliotransmitter highly expressed in energy balance centers including the hypothalamus and dorsal vagal complex. We previously demonstrated that targeting central or peripheral ODN signaling improves glycemic control and reduces body weight without nausea/emesis, making it an attractive target for metabolic disease. However, the systemic metabolic impact of ODN treatment remains poorly defined. We first identified that ODN regulates whole-body fuel usage assessed by respiratory quotient. Low-fat diet (LFD) and high-fat diet fed mice (n=8/diet/sex) demonstrated preferential fat utilization in the first two hours after intraperitoneal (IP) ODN treatment. Subsequently, ODN-treated mice only on LFD switched to burn more carbohydrates than controls. To understand if this shift in nutrient oxidation could be attributed to changes in cellular metabolic activity at peripheral tissues directly or through indirect action via the brain, we employed mitochondrial bioenergetics and metabolomics 1-hour post-intracerebroventricular (ICV) or IP treatment of ODN or vehicle in lean mice (n=3/treatment/sex). IP or ICV administered ODN did not alter mitochondrial respiration in brain, muscle, liver, or white adipose tissue of either sex. Metabolomics of medulla and muscle tissue revealed an influence of IP and ICV ODN on steroidogenesis, ether lipid metabolism, as well as histidine, beta-alanine, phenylalanine, and tyrosine metabolism. These data suggest that changes in oxidative respiration may not mediate ODN’s effects on systemic nutrient utilization, but amino acid metabolism may be at play. This work helps pinpoint the mechanisms underlying ODN’s metabolic regulation to further inform ODN analog treatment for metabolic disease.

Cognitive Restraint Is Associated With Reduced Energy Intake From Ultra-Processed Foods In An Inpatient Controlled Feeding Study
Hanna N. Salus, Juen Guo, Kevin Hall, Valerie L. Darcey
National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States

Ultra-processed foods (UPFs) promote excess energy intake (EI), weight gain, and dominate the current food environment. Eating behaviors are shaped by many factors, but susceptibility to overeating varies across individuals. We explored whether personality and eating traits explain differences in excess EI from a diet high in UPFs, energy density (ED), and hyper-palatability (HP). We hypothesized that higher cognitive restraint (CR) and conscientiousness and lower reward-based eating, disinhibition, and neuroticism would be associated with lower ad libitum EI on a UPF diet. In a randomized crossover inpatient feeding trial, healthy weight-stable adults (n = 36; age 36.3 ± 11.3 years; BMI 29.5 ± 7.0 kg/m²) consumed 7-day ad libitum diets matched for provided energy, macro/micronutrients but varying in ED, HP, and proportion of UPF. Here we report on: (1) high ED/HP with 80% kcal from UPFs, and (2) low ED/HP with no UPFs (minimally processed diet, MPF). Excess EI was defined as the difference in intake between the diets, adjusted for resting energy expenditure via indirect calorimetry. Personality and eating traits were assessed via validated questionnaires at standardized times. Significant associations met Spearman rank alpha of 0.05. Participants consumed 948 ± 419 kcal/day more on the UPF diet compared to MPF (95% CI 807–1090 kcal). Despite extant evidence suggesting links between conscientiousness, reward-based and disinhibited eating with weight status and EI, our exploratory results highlight a link between greater CR on the Three Factor Eating Questionnaire and lower excess EI on the UPF diet (ρ = −0.34, p = 0.04). Interventions to strengthen CR may be useful tools to optimize weight management in UPF-rich environments.

Sex-Dependent Effects Of Perinatal Bisphenol A Exposure On Body Composition And Metabolic Health In Offspring Mice
CL Sandoval-Caballero¹, B Kram¹, Z Roemer¹, A Ahmed¹, CM Kotz^1,2
¹Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, United States, ²Research Service, Minneapolis VA Health Care System, Minneapolis, MN, United States

Bisphenol A (BPA), a common component of consumer products, is associated with altered metabolic outcomes. In rodents, offspring of BPA-exposed dams show accelerated growth, increased fat mass, and impaired glucose tolerance in a dose- and sex-dependent manner. While BPA combined with a high-fat diet (HFD) worsens metabolic impairments in adult parent males, its effects in offspring remain controversial. We hypothesized that BPA-exposed offspring would exhibit worsened metabolic health, particularly when fed an HFD. To test this, fifty-five CD-1 offspring mice (29 BPA-exposed, 26 controls; 3 weeks old at baseline) were studied for 24 weeks with ad libitum access to a HFD or a control high-carbohydrate diet (HCD). Body weight (BW), body composition, and body length (BL) were assessed longitudinally. Food intake (FI), glucose tolerance (area under the curve, AUC), total energy expenditure (TEE), and locomotion were also measured. Mixed-effects models and t-tests were used for statistical analyses. BPA increased BW in females but not males, with earlier and stronger effects under HFD (p<0.001). This increase was not explained by adiposity, as fat mass and adiposity index were unchanged (p>0.05). Instead, BPA increased lean mass (LM) in females from ~10 weeks onward. Consistently, BPA-exposed females showed increased BL (p=0.00064), with no differences in males. FI, glucose tolerance, TEE, and locomotion were not affected by BPA (p>0.13), although males showed higher AUC than females (p=0.00014). Overall, perinatal BPA exposure increases BW in a sex-dependent manner, driven by increased LM and BL rather than adiposity. Studies are underway to assess whether increased LM and BL in females reflect skeletal muscle hypertrophy, including changes in myofiber diameter and muscle strength.

A Microstructural Analysis Of The Control Of Saline Ingestion In Male And Female Rats
Jessica Santollo¹, Emalie L. Mullane¹, Kennedy L. Lamb¹, Derek Daniels^2,3, Ann-Marie Torregrossa^2,4, Andrea A. Edwards¹
¹Department of Biology, University of Kentucky, Lexington, KY, United States, ²Center for Ingestive Behavior Research, University at Buffalo, Buffalo, NY, United States, ³Department of Biological Sciences, University at Buffalo, Buffalo, NY, United States, ⁴Department of Psychology, University at Buffalo, Buffalo, NY, United States

Lick microstructure analysis is a powerful tool used to analyze patterns of fluid and liquid food intake. This approach can provide insight about the mechanisms underlying observed changes in ingestion. Foundational work demonstrated that changes in the number of drinking bursts (at least 2 licks with an inter lick interval of <1s) reflect changes in negative feedback from post-oral sites related to satiety, whereas the average size of those bursts reflects changes in orosensory or hedonic value of the substance being consumed. These conclusions, however, were drawn from studies primarily using sucrose. While follow-up studies have examined the lick microstructure associated with water and saline intake, it is still unclear if the interpretation that changes in burst size being related to the hedonic value of the solution can be extended to saline. We tested the hypothesis that dehydrated rats would show a concentration dependent decrease in saline intake which would be mediated by reduced burst size. Twelve rats (6/sex) underwent 24-h water deprivation, followed by access to 0%, 1%, 2%, or 3% saline. Intake and licks were recorded for 1 h. This was repeated once a week for four weeks until all rats had access to all solutions. As expected, dose-related decreases in intake were observed (p <0.05). This reduction was mediated by decreased burst size (p <0.05), with no reduction in burst number (p = n.s.). In addition, males consumed more saline than females and had larger burst sizes than females (p <0.05). This finding supports the hypothesis that orosensory responsiveness plays a central role in the control of hypertonic saline and extends this work by demonstrating changes in burst size related to saline concentration.

Involvement Of Orexin And Light Environment In The Estrogen-Induced Hypophagia Through Circadian Feeding Regulation In Ovariectomized Rats
Akira Takamata¹, Natsumi Kosugi¹, Yuri Nishimura¹, Ayako Igarashi¹, Natsumi Omura¹, Keiko Morimoto^1,2
¹Nara Women's University, Nara, Japan, ²Kyoto Koka Women's University, Kyoto, Japan

Estrogen replacement in ovariectomized rats reduces food intake, particularly during the light phase. In the present study, we first examined the involvement of orexin A in this estrogenic effect. Estradiol (E2) replacement decreased food intake and attenuated activation of orexin A neurons in the perifornical/lateral hypothalamic area in response to insulin-induced hypoglycemia and 2-deoxy-D-glucose–induced glucoprivation, specifically during the light phase. We also found that exposure to a dark environment during the light phase (dark/dark environment) abolished the estrogen-induced attenuation of food intake and the enhancement of c-Fos expression in the suprachiasmatic nucleus (SCN) during the subjective day. Estrogen replacement increased non-REM sleep duration and decreased wakefulness during the light phase, and enhanced sleep induced by light exposure during the dark phase. These findings indicate that estrogen reduces food intake during the light phase, at least in part, by suppressing orexin neuron activity in a light-dependent manner. Light exposure during the light phase is required for the estrogen-induced hypophagia, and estrogen enhances response to light. In addition, adjustment of the feeding schedule diminished hyperphagia and excessive body weight gain induced by estrogen deficiency. Estrogen effectively attenuates food intake and weight gain by modulating the circadian regulation of feeding behavior through potentiated light-induced attenuation of feeding.

Central Amygdala Astrocytes Have Calcium Elevations During Food Consumption But Not In Response To Reward-Predictive Cues
Eeshi Uppalapati, Damien Kerspern, Andrew Lutas
Diabetes, Endocrinology, & Obesity Branch, NIDDK, NIH, Bethesda, MD, United States

Feeding is a complex behavior that requires the integration of external sensory cues with internal physiological states to guide goal-directed actions. The central amygdala (CeA) serves as a critical hub for reward processing, affective valence, and the regulation of feeding. Prior work has shown that dopamine is released during feeding, but this work has largely focused on neuronal populations. While astrocytes are increasingly recognized as modulators of neuronal network activity, their role in feeding-related behaviors remains poorly understood. Previous studies indicate that astrocytes actively regulate signaling transmission of the local neuronal network in the CeA. We hypothesize that CeA astrocytes respond to dopamine in this area and contribute to the modulation of feeding behavior. To test this, we performed calcium biosensor imaging via 2-photon microscopy on ex vivo brain slices from five mice, confirming that astrocytes directly respond to dopamine independently of neuronal activity. Then, using fiber photometry to record calcium biosensor dynamics, we monitored astrocytic calcium activity in the CeA of five mice engaged in Pavlovian feeding tasks. This revealed that astrocytic activity is modulated during ingestion, independent of internal state, and does not respond to reward-predictive cues. Moreover, astrocytic calcium dynamics track consummatory actions and appear insensitive to the identity or sensory properties of the ingested tastant. Collectively, these results suggest that CeA astrocytes directly detect dopamine and show elevated calcium in response. Furthermore, they support a role for astrocytes in CeA processing during consummatory behavior, positioning them as potential contributors to the neural mechanisms underlying feeding regulation.

Role Of The Bed Nucleus Of The Stria Terminalis In Vulnerability And Resilience To Activity-Based Anorexia
Julie D. Zhao^1,2, Ekaterina Likhtik^1,2, Nesha S. Burghardt^1,2
¹Hunter College, City University of New York, New York, NY, United States, ²The Graduate Center, City University of New York, New York, NY, United States

Activity-based anorexia (ABA) is a widely used animal model that combines restricted access to food with unlimited access to a running wheel. Similar to humans with anorexia nervosa, mice that are vulnerable to ABA increase voluntary exercise and fail to eat enough during food availability to compensate for energy expenditure, leading to life-threatening weight loss. In contrast, ABA resilient mice exhibit an adaptive increase in food intake and reduction in wheel running, leading to weight stabilization (Beeler et al., 2021). However, circuit-level changes mediating these two phenotypes have not been identified. Here, we show that exposure to acute restraint stress increases the proportion of mice that are ABA vulnerable (control: 47% vs. stress: 80%), implicating a role for stress-sensitive brain regions in the underlying pathophysiology. We are currently evaluating effects of ABA on neural activity in the bed nucleus of the stria terminalis (BNST), a brain region known to regulate stress response. Local field potentials (LFP) were recorded from the BNST in awake female mice (n=8) while they were inside a familiar chamber both before and after ABA. Raw LFP signals were filtered for both theta (3-7 Hz) and gamma (20-55 Hz) oscillations. Preliminary analyses (n=3) indicate that ABA vulnerability is associated with increases in BNST theta power and decreases in gamma power, reflecting changes in local network physiology. In ongoing analyses, we are characterizing oscillations in resilient mice and assessing synchrony between the BNST and the nucleus accumbens, a key node of the brain’s reward circuitry. This work will reveal neurophysiological signatures of vulnerability and resilience to ABA, providing much needed insight into mechanisms mediating anorexia nervosa.