Korean Journal of Biological Psychiatry

The effects of chronic treatment with haloperidol on the binding capacities of dopamine(DA) D2-like receptor were investigated in rat striatum and olfactory tubercle. The authors tried to confirm the dose-response effects with usual dose and low dose haloperidol. Rats were treated with haloperidol(0.05, 0.15, 0.5, 1.5mg/kg/day in drinking water) for four weeks. Saturation analysis of the binding of [³H]spiperone to striatal membranes showed that the haloperidol treatment(0.05, 0.5, 1.5mg/kg) induced significant proliferaton. The changes of dissociation constant(Kd) were not significant in striatum. The maximal binding density(Bmax) and Kd increased remarkably following the treatment with usual dose haloperidol(1.5mg/kg) in olfactory tubercle. Although there was increasing trend after the treatment with low dose haloperidol, the change of Bmax was not significant statistically. The present findings indicate that low dose haloperidol induces the proliferation of DA D₂-like receptor in striatum and interact with the dopaminergic transmission which might underlie the antipsychotic effect. This finding may support the recent clinical suggestion on the low dose strategy in the treatment of schizophrenia.

Keywords Haloperidol;Low dose;DA D₂ receptors;Striatum;Olfactory tubercle;[³H]spiperone.