Some effects of mazindol, an anorectic drug, on rat brain monoaminergic systems.

Mazindol was devoid of effect both on rat brain steady state levels of 5-HT, 5-HIAA and tryptophan and on the rate of synthesis of 5-HT in the rat brain. Mazindol had no effect on rat brain 5-HT uptake in vivo as determined by the effect of drug pretreatment on the ability of p-chloroamphetamine to lower central 5-HT levels. A large dose of mazindol caused a slight transient decrease in rat brain levels of NA and DA. Blockade of rat brain catecholamine uptake was quantified by studying drug effects on the ability of intraventricularly administered 6-hydroxydopamine to lower brain NA and DA content. Mazindol was an extremely potent inhibitor of rat brain NA uptake in vivo, being 4-5 times more potent than desipramine. Mazindol also blocked rat brain DA uptake. Doses of mazindol needed to release alpha-methyl-m-tyramine from the rat striatum were appreciably greater than the corresponding doses of d-amphetamine. The neurochemical profile of mazindol bears a much closer resemblance to that of d-amphetamine than to that of fenfluramine.