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Food history and social status affect food intake in monkeys
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Abstracts / Appetite 52 (2009) 815–868
Can liking of a healthy food increase with repeated exposure? M.A. MCCRORY 1,2,∗ , J.C. LOVEJOY 3 , M.M. GEHRKE 2 , P.A. PALMER 2 , P.E. EICHELSDOERFER 2 , I.T. KAVANAUGH 2 , K.E. SCHENK 2 1 Purdue University, West Lafayette, IN, USA 2 Bastyr University, Kenmore, WA, USA 3 Free & Clear, Seattle, WA, USA Repeated exposure to foods varying in selected sensory/nutrient properties (e.g., fat, salt, sugar, energy density) alters their appeal, but knowledge of the breadth of such learning is limited. We examined this issue using data from a partial-feeding study in which subjects (n = 43; aged 26–49 years; BMI 25–40 kg/m2 ) were randomly assigned to low, medium, or high legume (bean) groups as part of a weight-loss intervention. Subjects were not regular bean consumers. At 0 and 6 weeks, subjects tasted and rated multiple-ingredient foods for sensory qualities (appearance, taste, odor, and texture) using a 9-point hedonic scale. The 28-food test battery included a range of flavors and textures and was balanced with respect to foods provided/not provided in the study, and those with/without beans. We hypothesized that liking for bean-containing foods would increase in the medium bean group, but not in the low or high bean groups due to less than optimal and excessive exposure to beans, respectively. Repeated measures ANOVA showed greater increases in the hedonic ratings of provided foods compared to non-provided foods (provided = +0.2–0.3; non-provided = +0.1; p ≤ 0.001); however, these changes did not depend on whether the foods contained beans or the amount of beans provided during the study. Repeated exposure to specific foods can increase liking for those foods, including foods containing beans. Funding: Pulse Canada PIP; Hatch IND030472. doi:10.1016/j.appet.2009.04.138
DAMGO-induced stimulation of -opioid receptors in the mPFC leads to increases in food intake and a fragmentation of feeding microstructure J.D. MENA 1,∗ , B.A. BALDO 2 1 Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA 2 Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA The goal of the present study was to examine the role of the -opioid system within the mPFC on food intake and feeding microstructure. In both ad libitum and food restricted rats, bilateral infusions of the -agonist DAMGO within the mPFC significantly increased locomotor activity and fecal boli production, suggesting a highly aroused or stress-like state. Intra-mPFC DAMGO infusions also resulted in frequent feeding bouts in both groups, although the duration of these bouts was significantly shortened, as was the duration of rearing and grooming bouts. These changes in feeding microstructure resulted in significant increases in food intake. Interestingly, effects on drinking behavior were also found, with prandial drinking significantly reduced. This fragmentation of behavior was reminiscent of the effects of bicuculline, which disinhibits PFC activity, suggesting a common mechanism between both manipulations. In support of this idea, pre-treatment with the GABAA agonist, muscimol, attenuated the DAMGO-induced changes in feeding microstructure, further suggesting that the DAMGO effect is mediated by increased PFC activity. Together, these findings suggest a role for -opioid receptors within the mPFC on feeding microstructure and food intake. To the best of our knowledge, this is the first report of increased food intake following local -opioid receptor stimulation within the prefrontal cortex. doi:10.1016/j.appet.2009.04.139
Food history and social status affect food intake in monkeys V. MICHOPOULOS ∗ , K.N. SHEPARD, M. ARCE, J. WHITLEY, M.W. WILSON Emory University, Atlanta, GA, USA Chronic stress can lead to mood disorders that are often comorbid with a number of adverse health effects including changes in appetite. While stress may be associated with anorexia, availability of high caloric diets (HCD) can lead to excess calorie consumption. Using social subordination in female rhesus monkeys as a model of psychosocial stress, we tested the hypothesis that diet choice would influence total calorie intake. Using an automated feeding system that logs calorie consumption, daily calorie intake of a low calorie diet (LCD; 3.22 kcal/g) was significantly less in subordinates compared with dominant females, consistent with status differences in body weight and indices of adiposity. In contrast, when given a choice between the LCD and a HCD (5.64 kcal/g), subordinate females preferred the HCD and ingested significantly more calories per day than dominant animals. Under the choice condition, dominant monkeys also preferred the HCD but consumed a similar number of total calories as in the LCD only condition. When females were again fed only the LCD following the choice condition, subordinates continued to consume more calories than dominant females. Changes in metabolic phenotype and hormone levels were associated with increased calorie intake in subordinates. These data suggest that stress significantly increases consumption of a HCD and that previous exposure to a HCD increases intake of a LCD. The mechanisms accounting for the increased intake of the HCD in subordinates are not known at this time. Supported by HD46501 and RR00165. doi:10.1016/j.appet.2009.04.140
The anti-dipsogenic effect of ghrelin does not require the neuropeptide Y Y5 receptor E.G. MIETLICKI ∗ , D. DANIELS Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Buffalo, NY, USA Ghrelin attenuates angiotensin II (AngII)-induced water intake, but almost nothing is known about how or where in the brain this effect is mediated. In contrast, much is known about the effect of ghrelin on food intake, including its mediation of hyperphagia through neuropeptide Y (NPY). Because the drinking response to AngII requires forebrain substrates, and the hyperphagic effects of ghrelin in the forebrain depend on the NPY Y5 receptor, we tested if the attenuation of fluid intake by ghrelin also requires Y5 . To this end, we first replicated previous findings, showing that forebrain administration of a Y5 antagonist blocked the feeding effect of forebrain-delivered ghrelin. Using this paradigm, we tested the effects of a Y5 antagonist on both feeding and water intake. Specifically, rats were pretreated with a Y5 receptor antagonist or vehicle, followed by treatment with ghrelin or vehicle and AngII. Subsequent food and water intakes were measured. As shown previously, ghrelin-treated rats drank less in response to AngII than vehicletreated controls. Moreover, we found that the anti-dipsogenic effect of ghrelin was present even early in the light cycle when ghrelin did not increase feeding. These initial studies failed, however, to find evidence that Y5 is required for the anti-dipsogenic effect of ghrelin. Further studies are needed to clarify the specificity of these findings for AngII-induced intake and the potential role of other NPY receptors in the anti-dipsogenic effects of ghrelin. doi:10.1016/j.appet.2009.04.141
Abstracts / Appetite 52 (2009) 815–868
Can liking of a healthy food increase with repeated exposure? M.A. MCCRORY 1,2,∗ , J.C. LOVEJOY 3 , M.M. GEHRKE 2 , P.A. PALMER 2 , P.E. EICHELSDOERFER 2 , I.T. KAVANAUGH 2 , K.E. SCHENK 2 1 Purdue University, West Lafayette, IN, USA 2 Bastyr University, Kenmore, WA, USA 3 Free & Clear, Seattle, WA, USA Repeated exposure to foods varying in selected sensory/nutrient properties (e.g., fat, salt, sugar, energy density) alters their appeal, but knowledge of the breadth of such learning is limited. We examined this issue using data from a partial-feeding study in which subjects (n = 43; aged 26–49 years; BMI 25–40 kg/m2 ) were randomly assigned to low, medium, or high legume (bean) groups as part of a weight-loss intervention. Subjects were not regular bean consumers. At 0 and 6 weeks, subjects tasted and rated multiple-ingredient foods for sensory qualities (appearance, taste, odor, and texture) using a 9-point hedonic scale. The 28-food test battery included a range of flavors and textures and was balanced with respect to foods provided/not provided in the study, and those with/without beans. We hypothesized that liking for bean-containing foods would increase in the medium bean group, but not in the low or high bean groups due to less than optimal and excessive exposure to beans, respectively. Repeated measures ANOVA showed greater increases in the hedonic ratings of provided foods compared to non-provided foods (provided = +0.2–0.3; non-provided = +0.1; p ≤ 0.001); however, these changes did not depend on whether the foods contained beans or the amount of beans provided during the study. Repeated exposure to specific foods can increase liking for those foods, including foods containing beans. Funding: Pulse Canada PIP; Hatch IND030472. doi:10.1016/j.appet.2009.04.138
DAMGO-induced stimulation of -opioid receptors in the mPFC leads to increases in food intake and a fragmentation of feeding microstructure J.D. MENA 1,∗ , B.A. BALDO 2 1 Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA 2 Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA The goal of the present study was to examine the role of the -opioid system within the mPFC on food intake and feeding microstructure. In both ad libitum and food restricted rats, bilateral infusions of the -agonist DAMGO within the mPFC significantly increased locomotor activity and fecal boli production, suggesting a highly aroused or stress-like state. Intra-mPFC DAMGO infusions also resulted in frequent feeding bouts in both groups, although the duration of these bouts was significantly shortened, as was the duration of rearing and grooming bouts. These changes in feeding microstructure resulted in significant increases in food intake. Interestingly, effects on drinking behavior were also found, with prandial drinking significantly reduced. This fragmentation of behavior was reminiscent of the effects of bicuculline, which disinhibits PFC activity, suggesting a common mechanism between both manipulations. In support of this idea, pre-treatment with the GABAA agonist, muscimol, attenuated the DAMGO-induced changes in feeding microstructure, further suggesting that the DAMGO effect is mediated by increased PFC activity. Together, these findings suggest a role for -opioid receptors within the mPFC on feeding microstructure and food intake. To the best of our knowledge, this is the first report of increased food intake following local -opioid receptor stimulation within the prefrontal cortex. doi:10.1016/j.appet.2009.04.139
Food history and social status affect food intake in monkeys V. MICHOPOULOS ∗ , K.N. SHEPARD, M. ARCE, J. WHITLEY, M.W. WILSON Emory University, Atlanta, GA, USA Chronic stress can lead to mood disorders that are often comorbid with a number of adverse health effects including changes in appetite. While stress may be associated with anorexia, availability of high caloric diets (HCD) can lead to excess calorie consumption. Using social subordination in female rhesus monkeys as a model of psychosocial stress, we tested the hypothesis that diet choice would influence total calorie intake. Using an automated feeding system that logs calorie consumption, daily calorie intake of a low calorie diet (LCD; 3.22 kcal/g) was significantly less in subordinates compared with dominant females, consistent with status differences in body weight and indices of adiposity. In contrast, when given a choice between the LCD and a HCD (5.64 kcal/g), subordinate females preferred the HCD and ingested significantly more calories per day than dominant animals. Under the choice condition, dominant monkeys also preferred the HCD but consumed a similar number of total calories as in the LCD only condition. When females were again fed only the LCD following the choice condition, subordinates continued to consume more calories than dominant females. Changes in metabolic phenotype and hormone levels were associated with increased calorie intake in subordinates. These data suggest that stress significantly increases consumption of a HCD and that previous exposure to a HCD increases intake of a LCD. The mechanisms accounting for the increased intake of the HCD in subordinates are not known at this time. Supported by HD46501 and RR00165. doi:10.1016/j.appet.2009.04.140
The anti-dipsogenic effect of ghrelin does not require the neuropeptide Y Y5 receptor E.G. MIETLICKI ∗ , D. DANIELS Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Buffalo, NY, USA Ghrelin attenuates angiotensin II (AngII)-induced water intake, but almost nothing is known about how or where in the brain this effect is mediated. In contrast, much is known about the effect of ghrelin on food intake, including its mediation of hyperphagia through neuropeptide Y (NPY). Because the drinking response to AngII requires forebrain substrates, and the hyperphagic effects of ghrelin in the forebrain depend on the NPY Y5 receptor, we tested if the attenuation of fluid intake by ghrelin also requires Y5 . To this end, we first replicated previous findings, showing that forebrain administration of a Y5 antagonist blocked the feeding effect of forebrain-delivered ghrelin. Using this paradigm, we tested the effects of a Y5 antagonist on both feeding and water intake. Specifically, rats were pretreated with a Y5 receptor antagonist or vehicle, followed by treatment with ghrelin or vehicle and AngII. Subsequent food and water intakes were measured. As shown previously, ghrelin-treated rats drank less in response to AngII than vehicletreated controls. Moreover, we found that the anti-dipsogenic effect of ghrelin was present even early in the light cycle when ghrelin did not increase feeding. These initial studies failed, however, to find evidence that Y5 is required for the anti-dipsogenic effect of ghrelin. Further studies are needed to clarify the specificity of these findings for AngII-induced intake and the potential role of other NPY receptors in the anti-dipsogenic effects of ghrelin. doi:10.1016/j.appet.2009.04.141