Feeding parameters with two food textures after chlordiazepoxide administration, alone or in combination with d-amphetamine or fenfluramine.

Chlordiazepoxide (5.0, 10.0 mg/kg) reduced the rate of eating and extended the duration of feeding in a 10 min feeding test. It also reduced the latency to feed. Both fenfluramine (1.0 mg/kg) and d-amphetamine (0.25 mg/kg) acted to reduce food intake, but by differing mechanisms. Fenfluramine reduced eating rate without affecting eating duration, whilst d-amphetamine reduced eating duration without reducing eating rate. The effects of chlordiazepoxide on feeding parameters were generally additive with those of either d-amphetamine or fenfluramine, whenever chlordiazepoxide was given in combination with one of the anorectic drugs. Food texture affected feeding behaviour; rats ate standard diet in pellet form faster than powdered food, although they spent longer eating the powdered food. Textural differences did not significantly interact with the changes in feeding responses induced by the 3 drugs, except that latency to eat after either d-amphetamine or fenfluramine injection, when pellets were available, was significantly prolonged. Characterising drug effects on feeding in terms of a 2-dimensional matrix of eating rate and duration is recommended, rather than relying solely on amount of food consumption as the measure of drug effects.