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Food availability and control of binge eating
658
Abstracts / Appetite 54 (2010) 631–683
Preference for sucralose is associated with the number of fungiform papillae in rats G.C. LONEY ∗ , A.M. TORREGROSSA, L.A. ECKEL Florida State University, Tallahassee, FL, USA
Nucleus accumbens neurons encode the enhanced palatability of hypertonic saline following sodium depletion A.L. LORIAUX ∗ , J.D. ROITMAN, M.F. ROITMAN University of Illinois at Chicago, Chicago, IL, USA
Rats vary in their preference for sucralose. While sucralose preferers prefer sucralose over water across a range of sucralose concentrations, sucralose avoiders prefer water over concentrations of sucralose >0.1 g/L. Previously, we demonstrated that this preferer/avoider profile is influenced by individual differences in sensitivity to a bitter taste quality of sucralose. Because sex and strain can influence responsiveness to bitter/bittersweet compounds, our goal was to determine whether sucralose preference is influenced by sex or strain. Further data in humans suggests that increased sensitivity to bitterness is positively correlated with the number of fungiform papillae on the tongue. Thus, our second goal was to determine whether the number of fungiform papillae differ in sucralose preferers/avoiders. Male and female rats were given access to ascending concentrations of sucralose (0.0001–2.0 g/L) and water in two-bottle, 24-h preference tests. Neither the proportion of preferrers/avoiders nor the preference curves differed as a function of sex. The same experiment was conducted in male Long-Evans (LE) and Sprague–Dawley (SD) rats. LE preferrers, were more accepting of sucralose at all concentrations, relative to SD preferrers. No strain differences were detected among LE/SD avoiders. Examination of the tongues of a subset of LE rats revealed that sucralose avoiders had more fungiform papillae than sucralose preferrers (p < 0.05). We conclude that individual differences in the number of fungiform papillae predict sucralose avoidance/preference profiles in rats. doi:10.1016/j.appet.2010.04.117
The nucleus accumbens (NAc) differentially encodes the hedonic valence of taste stimuli. Appetitive tastes evoke phasic decreases in firing rate whereas aversive tastes evoke phasic increases. Here, we used sodium (Na+ ) depletion to ask whether NAc neurons can track changes in palatability of hypertonic saline (NaCl) due to a change in Na+ balance. Extracellular single-unit recordings were made in the rat to measure the activity of individual NAc neurons during brief (4 s, 200 L) intra-oral infusions of 0.45 M NaCl under different conditions (Na+ replete, deplete and re-replete). After each session, rats were given access to 0.45 M NaCl and distilled water in their home cages. Daily intakes were used to measure preference for NaCl. We hypothesized that the taste of NaCl would shift from unpalatable to palatable under the deplete condition, which would be encoded as a shift from overall increasing NAc activity to decreasing. In the NAc shell, recordings revealed that the shift from an increasing to a decreasing population response was due to an increase in the proportion of phasic decreases under the deplete condition rather than a change in the magnitude of individual neural responses. Thus, the NAc shell tracks enhanced palatability of a single taste stimulus by decreasing its activity. The role of these phasic decreases may be to disinhibit downstream areas such as the ventral pallidum in order to produce behavior. doi:10.1016/j.appet.2010.04.119
Weight suppression is a robust predictor of key features of bulimia nervosa M.R. LOWE 1,2 1 Drexel University, Philadelphia, PA, USA 2 The Renfrew Center, Philadelphia, PA, USA Food availability and control of binge eating A. LóPEZ-ESPINOZA ∗ , A.G. MARTíNEZ, F. DíAZ, K. FRANCO, V. ˜ M.G. RUELAS Feeding Behavior and NutriAGUILERA, C. MAGANA, tion Research Center, CUSur University of Guadalajara, México, Ciudad Guzmán, Jalisco, México, Mexico Probably the binge eating control is related to physiological, psychological and social factors. Nevertheless, an element of high importance is food availability. The objective of the present study was evaluating the effects of food availability control on the occurrence of binge eating behavior. Fifty albino rats (4-month-old at the beginning of the experiment) were divided in three groups. Groups 1 and 2 were deprived of food for a period of 72 h, and then returned to free food access according to one of the two procedures. The first procedure involved a return to the average of food intake registered during the baseline for 60 days, immediately return to free access. The second procedure involved return to free food access. Group 3 was exposed to free access all experiment. Water was freely available during the experiment. In second procedure, binge eating and excessive drinking were observed. In the first procedure binge eating and drinking were controlled by limiting food access. These results suggest that restriction of food availability could be a useful procedure to prevent eating disorders. doi:10.1016/j.appet.2010.04.118
Weight suppression (WS) is the difference between one’s current weight and highest ever body weight. Individuals with bulimia nervosa (BN) show elevated WS; recently there has been an upsurge in research on the role of WS in BN. Findings from our and other groups indicate that level of WS in BN (1) is related to more frequent binge eating and purging, (2) predicts weight gain over periods ranging from a few months to 5 years, (3) predicts poorer response to treatment in a clinical population receiving cognitive-behavioral therapy and a longer time period until remission from the disorder is achieved in a naturalistic, longitudinal study of BN, and (4) over a period of 10 years, predicts onset of BN-spectrum problems in those initially without them and, in those with a BN-spectrum problem, predicts a reduced probability of improvement 10 years later. Many covariates (e.g., current BMI, highest ever BMI, dieting frequency, subscales of the Eating Disorders Examination) have been tested but none have accounted for the predictive power of WS. These findings suggest that WS in BN may create a “biobehavioral bind” wherein greater WS induces more binge eating and weight gain, resulting in redoubled efforts at weight loss, thereby increasing WS and perpetuating a vicious cycle. Current approaches for treating BN do not take WS into consideration but perhaps should begin to do so. doi:10.1016/j.appet.2010.04.120
Abstracts / Appetite 54 (2010) 631–683
Preference for sucralose is associated with the number of fungiform papillae in rats G.C. LONEY ∗ , A.M. TORREGROSSA, L.A. ECKEL Florida State University, Tallahassee, FL, USA
Nucleus accumbens neurons encode the enhanced palatability of hypertonic saline following sodium depletion A.L. LORIAUX ∗ , J.D. ROITMAN, M.F. ROITMAN University of Illinois at Chicago, Chicago, IL, USA
Rats vary in their preference for sucralose. While sucralose preferers prefer sucralose over water across a range of sucralose concentrations, sucralose avoiders prefer water over concentrations of sucralose >0.1 g/L. Previously, we demonstrated that this preferer/avoider profile is influenced by individual differences in sensitivity to a bitter taste quality of sucralose. Because sex and strain can influence responsiveness to bitter/bittersweet compounds, our goal was to determine whether sucralose preference is influenced by sex or strain. Further data in humans suggests that increased sensitivity to bitterness is positively correlated with the number of fungiform papillae on the tongue. Thus, our second goal was to determine whether the number of fungiform papillae differ in sucralose preferers/avoiders. Male and female rats were given access to ascending concentrations of sucralose (0.0001–2.0 g/L) and water in two-bottle, 24-h preference tests. Neither the proportion of preferrers/avoiders nor the preference curves differed as a function of sex. The same experiment was conducted in male Long-Evans (LE) and Sprague–Dawley (SD) rats. LE preferrers, were more accepting of sucralose at all concentrations, relative to SD preferrers. No strain differences were detected among LE/SD avoiders. Examination of the tongues of a subset of LE rats revealed that sucralose avoiders had more fungiform papillae than sucralose preferrers (p < 0.05). We conclude that individual differences in the number of fungiform papillae predict sucralose avoidance/preference profiles in rats. doi:10.1016/j.appet.2010.04.117
The nucleus accumbens (NAc) differentially encodes the hedonic valence of taste stimuli. Appetitive tastes evoke phasic decreases in firing rate whereas aversive tastes evoke phasic increases. Here, we used sodium (Na+ ) depletion to ask whether NAc neurons can track changes in palatability of hypertonic saline (NaCl) due to a change in Na+ balance. Extracellular single-unit recordings were made in the rat to measure the activity of individual NAc neurons during brief (4 s, 200 L) intra-oral infusions of 0.45 M NaCl under different conditions (Na+ replete, deplete and re-replete). After each session, rats were given access to 0.45 M NaCl and distilled water in their home cages. Daily intakes were used to measure preference for NaCl. We hypothesized that the taste of NaCl would shift from unpalatable to palatable under the deplete condition, which would be encoded as a shift from overall increasing NAc activity to decreasing. In the NAc shell, recordings revealed that the shift from an increasing to a decreasing population response was due to an increase in the proportion of phasic decreases under the deplete condition rather than a change in the magnitude of individual neural responses. Thus, the NAc shell tracks enhanced palatability of a single taste stimulus by decreasing its activity. The role of these phasic decreases may be to disinhibit downstream areas such as the ventral pallidum in order to produce behavior. doi:10.1016/j.appet.2010.04.119
Weight suppression is a robust predictor of key features of bulimia nervosa M.R. LOWE 1,2 1 Drexel University, Philadelphia, PA, USA 2 The Renfrew Center, Philadelphia, PA, USA Food availability and control of binge eating A. LóPEZ-ESPINOZA ∗ , A.G. MARTíNEZ, F. DíAZ, K. FRANCO, V. ˜ M.G. RUELAS Feeding Behavior and NutriAGUILERA, C. MAGANA, tion Research Center, CUSur University of Guadalajara, México, Ciudad Guzmán, Jalisco, México, Mexico Probably the binge eating control is related to physiological, psychological and social factors. Nevertheless, an element of high importance is food availability. The objective of the present study was evaluating the effects of food availability control on the occurrence of binge eating behavior. Fifty albino rats (4-month-old at the beginning of the experiment) were divided in three groups. Groups 1 and 2 were deprived of food for a period of 72 h, and then returned to free food access according to one of the two procedures. The first procedure involved a return to the average of food intake registered during the baseline for 60 days, immediately return to free access. The second procedure involved return to free food access. Group 3 was exposed to free access all experiment. Water was freely available during the experiment. In second procedure, binge eating and excessive drinking were observed. In the first procedure binge eating and drinking were controlled by limiting food access. These results suggest that restriction of food availability could be a useful procedure to prevent eating disorders. doi:10.1016/j.appet.2010.04.118
Weight suppression (WS) is the difference between one’s current weight and highest ever body weight. Individuals with bulimia nervosa (BN) show elevated WS; recently there has been an upsurge in research on the role of WS in BN. Findings from our and other groups indicate that level of WS in BN (1) is related to more frequent binge eating and purging, (2) predicts weight gain over periods ranging from a few months to 5 years, (3) predicts poorer response to treatment in a clinical population receiving cognitive-behavioral therapy and a longer time period until remission from the disorder is achieved in a naturalistic, longitudinal study of BN, and (4) over a period of 10 years, predicts onset of BN-spectrum problems in those initially without them and, in those with a BN-spectrum problem, predicts a reduced probability of improvement 10 years later. Many covariates (e.g., current BMI, highest ever BMI, dieting frequency, subscales of the Eating Disorders Examination) have been tested but none have accounted for the predictive power of WS. These findings suggest that WS in BN may create a “biobehavioral bind” wherein greater WS induces more binge eating and weight gain, resulting in redoubled efforts at weight loss, thereby increasing WS and perpetuating a vicious cycle. Current approaches for treating BN do not take WS into consideration but perhaps should begin to do so. doi:10.1016/j.appet.2010.04.120