Influence of fenfluramine and norfenfluramine stereoisomers on the firing rate of central monoaminergic neurons in the rat

Abstract

The influence of acute administration of stereoisomers of fenfluramine and norfenfluramine on the firing rate of central monoaminergic neurons was investigated in rats anaesthetized with chloral hydrate. The firing rate of dorsal raphe (DR) and locus coeruleus (LC) neurons was inhibited. The parent drugs were more active on DR neurons than on LC neurons, and the converse was true for the demethylated metabolites. In both cases the d isomers were more active than the 1 isomers. No effect was observed on the electrical activity of A10 dopaminergic neurons. These differences in potency and selectivity could have therapeutic implications. © 1990.