Academic literature on the topic 'Anorectic behavior'

Abstract Food intake in most mammals is behaviourally complex. In the rat larger amounts are eaten at the beginning and end of the night with relatively lower consumption during the day. In addition, food is consumed in ‘meals’- periods of relatively intense feeding behaviour occupying 2-5 per cent of the animal’s time budget. Changes in food intake may be achieved by modulating meal size, meal frequency, or some combination of both together with readjustment of the usual diurnal intake pattern. The analysis of pharmacologically induced changes in food intake has become widely used in recent years (Clifton 1987).Chronic meal-contingent infusion of CCK substantially and permanently reduces meal size, although meal frequency increases so that the total food intake is only slightly reduced for the first 2 or 3 days and subsequently is no different from control levels (West et al. 1984). The indirect serotonin agonist DL-fenfluramine also reduces food intak , primarily by reducing meal size (Popplewell et al. 1981). As tolerance to the anorectic effect of fenfluramine develops and overall food intake increases, meal size remains reduced and meal frequency increases (Barnfield and Clifton, unpublished data). In both cases the reduction in meal size has been taken as evidence of an effect on satiety rather than hunger.Recent evidence suggests possible interactions between CCK and 5-hydroxytryptamine (5-HT) in the control of feeding. Stallone et al. (1989) have shown that the 5-HT antagonist metergoline blocks the anorectic action of CCK-8 in short-term intake tests. They favoured a central site for this interaction in which the antagonist blocked a vagally transmitted peripheral CCK signal. Cooper _et al. (1990) have demonstrated a rather different interaction. They showed that the CCK antagonist devazepide, at a dose which when given alone had little effect on intake, could block the. anorectic effect of o-fenfluramine. Their study also used a simple short-term intake test. Here we report a meal pattern study in which the same drug interaction is examined.