Effects of sustained central infusion of bombesin (BN) or its antagonist on ingestive behavior of rats. Z. MERALI and C. LAMBERT. School of Psychology and Department of Pharmacology, University of Ottawa, Ottawa, Ontario, Canada Kl N 9A9.
Acute BN administration reduces meal size in fasted animals. The objective of the current study was to characterize the effects of g-day sustained central administration of BN (0, 0.01, 0.05, 0.1 and 5 pg/h) or its antagonist (AN) (BIM-26226; 0, 0*005, 0.05, O-5 and 5 pg/h), in free-feeding rats. Each dose was delivered over 48 h, in an ascending sequence. A meal was defined as a feeding bout of at least 0.2 g, separated by at least 5 min of no feeding responses. Over the ten 23-h observation sessions, the control rats consumed an average of 27.9g powdered chow/day [84% in dark (D) phase], 21 meals (76% in the D phase) with average meal duration of 7.3 min. At the higher doses, the BN group consumed significantly less and the AN group significantly more than the controls, during the D phase. There were no differences in the body weight gain between the BN and the AN groups. Following food deprivation (14 h over D phase) BN-pretreated rats consumed significantly less of the test meal than the control or AN-pretreated rats. Following acute systemic BN (8 pg/kg; i.p.) food consumption was suppressed in all three groups. Although the food intake was similar at 30 min in all three groups, it was lower for the BN group, at 60 min. These data support the contention that certain central endogenous BN-like peptides may play a physiological role in the modulation of feeding behavior. It appears that BN may play a greater role in mechanisms operating under emergency or fasting states than those involved in the long-term regulation of food intake. These data also suggest potential clinical utility of BN antagonists in anorexia nervosa, cancer anorexia and bulimia.
Short-term consumption and lick analysis of saccharine-ethanol cocktails by rats. J. C. MITCHELL and C. C. HORN. Department of Psychology, Kansas State University, Manhattan, KS 66506, U.S.A.
Most laboratory studies of alcohol ingestion in rats involve presentations of alcohol-water mixtures, yet in the normal world of humans, alcohol is mixed with another pleasant tasting substance, often something sweet. For this reason we chose to present Na Saccharine (0.006 M w/v) or 3, 5, 9, or 12% Na Saccharine-alcohol mixtures. Three similar studies involving only minor differences N-4, 5, and 5) were carried out using one bottle consumption and lick analysis. In each experiment, rats were tested 0.5 h following the beginning of the night period of a reverse 12 h day-night cycle. Initially, rats were allowed to drink the 0.006 M Na saccharine. Volumes ingested were measured and photocell drinkometers recorded licking. Licks were recorded using a computer. After attaining stable liquid intakes, rats were given 3, 6, 9, and 12% alcohol-Na Saccharine solutions, first in ascending order followed by descending orders of concentration to counterbalance for order effects. Consumption of the saccharine and 3% alcohol mixtures were not significantly different, but was greater than that of the other three mixtures, which in turn, were different from each other (all ps