Effects of Mg-pemoline on the central catecholaminergic system.

Acute or repeated treatment with Mg-Pemoline (Mg-Pg) did not modify the endogenous level of brain catecholamines (CA) of rats. However, a single dose (30 mg/kg) produced a significant decrease of brain CA turnover, measured either by the rate of conversion of 14C-tyrosine to CA or by the rate of disappearance of CA after alpha-MT. Mg-Pe (0.01-0.1 mM) did not modify the basal outflow nor the release of 3H-DA elicited by high K+ in slices of corpus striatum. At the same concentrations, Mg-Pe inhibited uptake of DA (competitively) or NA (uncompetitively) in synaptosomes from corpus striatum and hypothalamus, respectively. Turning-behavior in mice lesioned in corpus striatum with 6-OH-DA, indicated that this drug acts like amphetamine as an indirect DA agonist. These results suggest that central stimulant effects of Mg-Pe may be the consequence of CA-uptake inhibition and this effect may also account for the decrease of brain CA turnover.