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Biomedical subjects

B A Gosnell

Publications and source records attributed to B A Gosnell.

At least 19 recordsLinked to original sources
PubMed2001

Food presentation and energy intake in a feeding laboratory study of subjects with binge eating disorder.

OBJECTIVE: The purpose of this study was to examine the influence of the number of foods presented and the amount of food presented on overeating or binge eating behavior in obese subjects with and without binge eating disorder (BED). METHOD: Ten subjects (5 BED, 5 non-BED), male and female, aged 18-65, participated. Their body weight was > or =130% of their ideal body weight (IBW). They were evaluated in a feeding laboratory setting on four occasions when they were presented with (a) either one or two binge foods presented in (b) either two or four times the amount of their self-reported usual intake during a binge/overeating episode. Measurement included energy intake and self-recorded measures of hunger, fullness, anxiety, and depression. RESULTS: The results indicated that the number and amount of food presented influenced significantly the amount of food consumed. Although subjects with BED tended to eat more than the non-BED obese, the differences did not reach statistical significance. DISCUSSION: The results have implications for the interpretation of results obtained in feeding laboratory settings, suggesting that attention needs to be given to both the number and amount of foods presented because both variables have an impact on the amount of food eaten during overeating or binge eating episodes.

Adolescent↗
PubMed2001

Long-term follow-up of patients' status after gastric bypass.

BACKGROUND: We report a long-term (13-15 year) follow-up of a cohort of 100 patients who underwent gastric bypass for morbid obesity. METHODS: Sources of information include baseline data collected before surgery and information obtained at follow-up interview including data on weight history, psychosocial functioning, and medical complications. RESULTS: Mean age at follow-up was 56.8 years. The mean weight loss at long-term follow-up was 29.5 kg (range -13.6 to 93.6 kg). Three subjects weighed more at long-term follow-up than before the operation. Overall, 74% of those interviewed indicated that the gastric bypass had benefited them in terms of their physical health. However, 68.8% reported continued problems with vomiting and 42.7% with "plugging". Eight had died. CONCLUSION: The findings in this study suggest that at long-term follow-up the majority of individuals who have undergone gastric bypass feel that the procedure benefited them, although some complications including difficulties with "plugging" and vomiting were present at long-term follow-up.

Adaptation, Psychological↗
PubMed2000

Sucrose intake predicts rate of acquisition of cocaine self-administration.

RATIONALE: A number of studies have indicated a relationship between the intake of palatable foods or fluids and drug self-administration. OBJECTIVES: Two experiments were conducted to determine whether the intake of sucrose or fat was related to subsequent cocaine self-administration. METHODS: In separate groups of rats, sucrose or fat was presented for 60 min daily for 7 days. On day 8, a mild stressor (saline injection) was given just prior to sucrose or fat presentation. Rats were then catheterized and tested for cocaine self-administration on a fixed ratio schedule at doses from 0.2 mg/kg to 1.0 mg/kg per infusion and on a progressive ratio schedule at doses from 0.2 mg/kg to 1.5 mg/kg per infusion. RESULTS: Sucrose intake after a mild stressor was significantly related to time to acquisition, with those rats consuming the most sucrose meeting the acquisition criterion sooner than those rats consuming lower amounts of sucrose. Subsequent to acquisition, however, low and high sucrose feeders did not consistently differ in the amount of cocaine self-administered. No relationship was observed between fat intake and rate of acquisition. CONCLUSION: These results provide additional evidence of a relationship between sucrose intake and drug reward, and suggest that stress reactivity may be an important component of this relationship.

Animals↗
PubMed1998

The relationship between intravenous cocaine self-administration and avidity for saccharin.

Two experiments were conducted to determine whether measures of saccharin intake could be used as a predictor of intravenous cocaine self-administration. Saccharin avidity, defined as the ratio of total daily fluid intake when saccharin and water were available to total intake when only water was available, was measured in male rats. Cocaine self-administration (0.4 mg/kg/infusion) was subsequently measured in an initial 18-h session, followed by daily 1-h sessions in which the infusion dose and the reinforcement schedule were varied. In the initial overnight session, some rats obtained the maximum or near-maximum number of infusions; this high level of cocaine intake was unrelated to saccharin avidity. In the remaining rats, there was a pattern somewhat resembling an "inverted-U," in which rats with low or high avidity self-administered less cocaine than those with intermediate avidity. This pattern reemerged later in the experiment when rats were tested at a low cocaine infusion dose combined with a FR-6 reinforcement schedule. In a second experiment, no significant relationship was observed between the self-administration of a lower cocaine dose (0.125 mg/kg/infusion) and avidity for either saccharin or the artificial sweetener SC-45647. Although these results are consistent with a previous report indicating no simple relationship between saccharin preference and the acquisition of cocaine self-administration, they do suggest that a more complex relationship may be observed under some conditions. Additional research with other drugs, as well as with caloric and noncaloric sweeteners, will be needed to determine the usefulness of taste measures in identifying or treating substance abuse.

Animals↗
PubMed1998

Intake of high-fat food is selectively enhanced by mu opioid receptor stimulation within the nucleus accumbens.

The present study was designed to further investigate the nature of feeding induced by opioid stimulation of the nucleus accumbens through an examination of the effects of intra-accumbens (ACB) opioids on macronutrient selection. In 3-hr tests of free-feeding (satiated) rats, intra-ACB administration of the mu receptor agonist D-Ala2,N,Me-Phe4, Gly-ol5-enkephalin (DAMGO; 0, 0.025, 0.25 and 2.5 micrograms bilaterally) markedly enhanced the intake of fat or carbohydrate when the diets were presented individually (although the effect on fat intake was much greater in magnitude). Intra-ACB injections of DAMGO, however, produced potent preferential stimulatory effects on fat ingestion with no effect on carbohydrate ingestion when both fat and carbohydrate diets were present simultaneously. Moreover, this selective stimulation of fat intake was independent of base-line diet preference and could be blocked by systemic injection of naltrexone (5 mg/kg). We also examined the effect of 24-hr food deprivation on the pattern of macronutrient intake in rats with access to both carbohydrate and fat. In contrast to the DAMGO-induced selective enhancement of fat intake, food deprivation significantly increased the intake of both diets to the same extent; however, in this case, only the stimulated fat intake was blocked by systemic naltrexone. Intra-ACB administration of DAMGO in hungry rats produced an effect similar to that observed in free-feeding rats; preference was strongly shifted to fat intake. Similarly, the opioid antagonist naltrexone (20 micrograms) infused directly into ACB preferentially decreased fat intake in hungry rats. These findings suggest that endogenous opioids within the ventral striatum may participate in the mechanisms governing preferences for highly palatable foods, especially those rich in fat.

Animals↗
PubMed1995

Clinical characteristics of eating disorder patients who report sexual or physical abuse.

At initial contact in an eating disorders clinic, 712 female eating disorder patients were asked if they had been physically or sexually abused as children. They also completed a Beck Depression Inventory (BDI) and an Eating Disorders Inventory (EDI). Their eating disorder symptom frequency and severity was determined. They were asked if they had alcohol problems, had attempted suicide, or had shoplifting problems. Twenty-nine percent reported sexual abuse. Twenty-five percent reported physical abuse. There was no correlation between reports of abuse and symptom frequency or severity. The abused subjects were more depressed on the BDI and showed more psychological disturbance on the EDI. Abused subjects were much more likely than nonabused subjects to report alcohol problems, suicide attempts, or shoplifting.

Adolescent↗
PubMed1995

Intravenous morphine self-administration by rats with low versus high saccharin preferences.

An experiment was performed to determine the relationship between saccharin preference and the self-administration of morphine via the oral and intravenous routes. On the basis of voluntary intake of a saccharin solution by male rats, low and high preference groups were formed. Rats selected for high saccharin preference self-administered more morphine intravenously than rats selected for low preference. The two groups did not differ in oral morphine intake. The positive relationship between the intake of saccharin and intravenous morphine self-administration may be due to their mediation by a common mechanism. Measures of taste sensitivity or preference may be useful in identifying individuals at risk for drug abuse.

Administration, Oral↗
PubMed1995

Naloxone, an opiate blocker, reduces the consumption of sweet high-fat foods in obese and lean female binge eaters.

To test the hypothesis that endogenous opiate peptides selectively influence hedonic response to sweet and high-fat foods, the opiate antagonist naloxone, opiate agonist butorphanol, and a saline placebo were administered by intravenous infusion to 16 obese and 25 normal-weight women. Twenty of the women (10 obese, 10 lean) fulfilled DSM-III-R diagnostic criteria for bulimia nervosa, as determined by psychiatric interview. During drug infusion the women tasted and rated 20 sweetened dairy products and were presented with eight snack foods of varying sugar and fat content. Naloxone suppressed hedonic responses in all subject groups and suppressed the consumption of sweet and high-fat foods in binge eaters, but not in nonbingers. Food intakes of obese women were not affected by naloxone. Butorphanol had no effect on either hedonic response or on food consumption in any group. Although opiate blockade is not a viable strategy for weight reduction in the treatment of obesity, it may be useful in the clinical management of the binge-eating disorder.

Adult↗
PubMed1993

The effects of continuous morphine infusion on diet selection and body weight.

The administration of morphine causes a short-term increase in food intake, and repeated administration of morphine has been shown to cause progressively larger increases in intake and/or the relative intake of dietary fat. In this experiment, we measured the effects of continuous morphine infusions on diet choice and total intake. Male rats were given ad lib access to two diets: a high-carbohydrate diet (80% carbohydrate, 20% protein) and a high-fat diet (80% fat, 20% protein). Diet intakes were measured daily for 21 days. Via the implantation of osmotic minipumps, one group received continuous infusions of morphine sulfate (approx. 2.8 mg/kg/h) for days 1-7 and of saline for days 8-14. A second group was infused with saline for days 1-7 and with morphine for days 8-14. A third group received sham surgery but no minipumps. Total caloric intake was significantly decreased on the final 6 days of morphine infusions. The percentage of total caloric intake consumed from the high-fat diet was significantly increased for the first 2-3 days of morphine treatment; this effect was due to an initial reduction in carbohydrate intake and an increase in fat intake. Over the course of the infusion period, fat intake gradually decreased and carbohydrate intake increased. The effects of morphine when infused on days 1-7 were similar to those observed when the drug was infused during days 8-14.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Morphine-induced feeding: a comparison of the Lewis and Fischer 344 inbred rat strains.

Rats of the Lewis inbred strain have been shown to self-administer more morphine than rats of the inbred Fischer 344 (F344) strain. Because morphine reward and opioid-induced feeding may involve a common mechanism, we measured whether these strains also differ in their feeding response to morphine. In Experiment 1, rats were maintained on powdered rat chow and given SC injections of morphine sulfate (1, 3, and 10 mg/kg) and saline; all rats were tested with all doses. Food intake was measured 2, 4, and 6 h after injection. In Experiment 2, rats were given a choice of two diets: a fat/protein diet and a carbohydrate/protein diet. Feeding responses to morphine were measured in a manner identical to that in Experiment 1. In both experiments, the feeding response to morphine was greater in Lewis rats than in F344 rats. To determine whether these responses might be explained by differences in the levels of morphine achieved in the blood or brain, rats of each strain were given SC injections of morphine sulfate (3 mg/kg) and sacrificed either 30 min or 3 h after injection. Serum and brain morphine levels were determined by radioimmunoassay. Lewis rats had significantly less brain morphine than F344 rats at 30 min; they did not differ in morphine content at 3 h. Serum levels were similar at 30 min; at 3 h, F344 rats had slightly lower levels than Lewis rats. Thus, differences in tissue levels cannot readily explain the differences in feeding responses to morphine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Centrally administered mu- and delta-opioid agonists increase operant responding for saccharin.

In previous reports, ICV administration of selective mu- or delta-opioid receptor agonists was found to stimulate the intake of saccharin and salt solutions in nondeprived rats. In the present study, we measured the effects of selective mu-, delta-, and kappa-agonists on operant responding for saccharin. The selective mu-agonist [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin (DAMGO) and the selective delta-agonist [D-Thr2]-leucine enkephalin-Thr (DTLET) increased responding, whereas the kappa-agonist dynorphin A analog kappa ligand (DAKLI) had no significant effect. These results agree with previous studies on saccharin and salt intake and are consistent with the possibility that the effects of opioids on the intake of these fluids are mediated via enhancement of activity in brain reward pathways.

Amino Acid Sequence↗
PubMed1993

Morphine enhances hedonic taste palatability in rats.

The question of whether opiates stimulate feeding by enhancing taste pleasure was investigated by examining the effect of morphine upon hedonic and aversive reactions to taste (tongue protrusions, gapes, etc.). Rats (n = 12) were given SC injections of morphine (4 mg/kg) or equal volumes of isotonic saline 2 h after the start of their daily light cycle. Food intake was measured in a 2-h test. On days when they were given morphine, rats ate significantly more food than when given saline. Hedonic and aversive taste reactions were elicited by an infusion of sucrose-quinine solution into the mouth and were measured subsequently in a slow-motion video analysis. The same rats that showed an increase in food intake after treatment with morphine showed a significant increase in their positive hedonic responses. Aversive reactions were unchanged by morphine. The results support the hypothesis that morphine enhances feeding by increasing the hedonic palatability of food.

Animals↗
PubMed1992

The effects of continuous naltrexone infusions on diet preferences are modulated by adaptation to the diets.

Two groups of male rats were placed on a feeding regimen in which a fat/protein diet and a carbohydrate/protein diet were available ad lib. Naltrexone was infused via osmotic minipumps either at the time the diets were introduced or after one week of adaptation to the diets. In rats adapted to the diets, naltrexone caused a decrease in the intakes of fat/protein and carbohydrate/protein diets. Relative preferences for the two diets were generally unchanged. In contrast, when naltrexone was infused at the time of introduction of the diets, a polarization phenomenon was observed: rats tended to consume nearly all of their daily calories from either one diet or the other. Six rats (out of 10) showed a stronger preference for the carbohydrate/protein diet than did any of the saline-treated rats, while 3 showed a stronger preference for the fat/protein diet than did any of the saline-treated rats. Thus, the effect was not diet- or macronutrient-specific. These preferences became significantly less extreme after termination of naltrexone infusions. Conditioned aversions and naltrexone-induced reductions in exploratory behavior are discussed as potential explanations for this polarization effect. These results indicate that naltrexone has differential effects on the development versus the maintenance of diet preferences. Further, they emphasize the importance of examining individual differences as well as baseline preferences in studies on the control of intake and diet selection.

Adaptation, Psychological↗
PubMed1992

Taste responses and preferences for sweet high-fat foods: evidence for opioid involvement.

Preferences and cravings for sweet high-fat foods observed among obese and bulimic patients may involve the endogenous opioid peptide system. The opioid antagonist naloxone, opioid agonist butorphanol, and saline placebo were administered by intravenous infusion to 14 female binge eaters and 12 normal-weight controls. Eight of the binge eaters were obese. During infusion, the subjects tasted 20 sugar/fat mixtures and were allowed to select and consume snack foods of varying sugar and fat content. Naloxone reduced taste preferences relative to baseline in both binge eaters and controls. Total caloric intake from snacks was significantly reduced by naloxone in binge eaters but not in controls. This reduction was most pronounced for sweet high-fat foods such as cookies or chocolate. No consistent effects on taste preferences or food intakes were observed with butorphanol. Endogenous opioid peptides may be involved in mediating taste responses and preferences for palatable foods, notably those rich in sugar and fat.

Adolescent↗
PubMed1991

Stealing in eating disordered patients.

Previous studies have noted high rates of stealing behavior in patients with eating disorders. To assess the significance of stealing in eating disordered patients, the authors compared the eating and purging behavior, levels of psychologic symptomatology, and alcohol use of 181 eating disordered patients with and without a history of stealing. Overall, the patients with a history of stealing had significantly more dysfunctional eating and purging behavior. Those patients with a history of stealing reported significantly more psychological distress including more depression, interpersonal sensitivity, obsessive compulsive behavior, and hostility. The authors conclude that stealing behavior should be assessed in patients with eating disorders as a history of stealing may define a subgroup of more severely impaired patients.

Adolescent↗
PubMed1990

The anorectic effects of CRH and restraint stress decrease with repeated exposures.

Intracerebroventricular (icv) administration of corticotropin-releasing hormone (CRH) or exposure to a restraint stressor causes acute anorexia in rats. However, the effects on food intake of repeated injections of CRH or repeated exposures to restraint stress have not been previously reported. As the effects of these more chronic CRH and stress treatments may be of greater relevance to emerging hypotheses of the pathogenesis of human eating and affective disorders, we measured the changes in food intake and body weight of rats after repeated central injections of CRH. In two experiments using two different daily dosages of CRH and two different schedules of administration, we found that the anorectic effect of CRH decreased over repeated injections. Weight gain was slowed significantly only in the high-dose experiment. Rats may become tolerant to the anorectic effects of CRH delivered by repeated icv injections. These findings have important implications for hypothesized mechanisms of anorexia nervosa and/or depression.

Animals↗
PubMed1990

Effects of a selective mu opioid receptor agonist and naloxone on the intake of sodium chloride solutions.

Endogenous opioid peptides are thought to play a role in mediating the palatability or rewarding aspects of sweet tastes. There is also evidence, however, which suggests that opioids may influence the preference for the taste of salt as well. In the present studies, we measured the effects of central administration of naloxone and the mu agonist [D-Ala2,MePhe4,Gly-ol5]enkephalin (DAGO) on the ingestion of salt solutions. In non-deprived rats given a choice of water and 0.6% saline, ICV injections of DAGO (1 and 3 nmol) significantly increased the intake of 0.6% saline; baseline water intake was minimal and was unaffected by DAGO. When rats were given a choice between water and 1.7% saline, DAGO stimulated both water and saline intake. Because 1.7% saline is a hypertonic solution, the increase in water intake may have been secondary to saline intake. In rats on a deprivation schedule in which water and 0.6% saline were available for only 2-3 h/day, there was a tendency for DAGO to increase 0.6% saline intake and decrease water intake, though these effects were not significant. In rats given water and 1.7% saline, DAGO increased saline intake and had no effect on water intake. Naloxone was also tested in water-deprived rats. Naloxone (20 and 50 micrograms) significantly decreased 0.6% saline intake; baseline water intake was low (3-5 ml) and was unaffected by naloxone. When rats were given a choice between water and 1.7% saline, naloxone (50 micrograms) significantly reduced water intake, while intake of 1.7% saline was slightly increased. These results suggest a role for central mu opioid receptors in mediating the preference for salt solutions.

Animals↗