The effects of d-fenfluramine on saccharin intake and preference, and on food and water intake

Abstract

The effects of d-fenfluramine on saccharin intake and preference were examined to investigate whether the reduced rate of eating induced by this compound reflects a reduction in the palatability of foods. In two separate experiments, water deprived rats were offered a choice between a 0.05% solution of saccharin and water, or a 0.2% saccharin solution and water. Injection of d-fenfluramine at doses which reliably decreased food intake resulted in dose dependent reductions in total fluid intake and saccharin intake. A trend towards reduced water intake was observed also, and this together with the reduced saccharin intake resulted in no overall change in saccharin preference. In a further experiment, d-fenfluramine reduced the water intake of water deprived rats to the same extent as it reduced total fluid intake in the chouce tests. Since d-fenfluramine failed to alter saccharin preference, it is unlikely that the slowed eating rate induced by this compound indicates a reduction in food palatability. Instead, it is likely that this behaviour results from a subtle motor deficit, such that fenfluramine treated animals are unable to maintain ingestion at the same rate as non-drugged animals. This explanation could account for the reduction in the consumption of non-nutritive saccharin solutions and water in water deprived animals. The relevance of this action to the anorectic effect of fenfluramine is discussed.