[Effects of psychotropic drugs on lateral hypothalamic self-stimulation behavior in rats: correlation between self-stimulation behavior inhibition and striatal dopaminergic blockade by neuroleptic drugs].

The effects of neuroleptic drugs on self-stimulation behavior were investigated in rats with electrodes chronically implanted in the lateral hypothalamus. Except for sulpiride and carpipramine, the neuroleptic drugs chlorpromazine, thioridazine, perphenazine, haloperidol, floropipamide, pimozide, clocapramine and oxypertine all suppressed self-stimulation behavior dose-dependently. The anti-anxiety drugs chlordiazepoxide, diazepam, clotiazepam and etizolam facilitated this behavior. The antidepressant drugs imipramine and amitriptyline suppressed this behavior slightly at the dose of 40 mg/kg. The alpha-antagonist phenoxybenzamine also suppressed this behavior, but the slope of its dose-response curve was gentle compared with those of the neuroleptic drugs. The inhibition produced by the neuroleptic drugs is considered to be mediated primarily at the dopaminergic receptors. Turning behavior induced by methamphetamine in rats with unilateral 6-hydroxydopamine lesions of the caudate nucleus was used to assess the striatal dopaminergic blocking potency of the neuroleptic drugs. No correlation was found between the ED50 values for the turning behavior inhibition and the ED50 values for the self-stimulation behavior inhibition produced by these drugs, so the dopaminergic receptors in the striatum are apparently not involved in the mediation of self-stimulation behavior.