Characterization of D2-dopamine receptor modification in rat striatum after calcium channel blocker treatment.

A wide variety of chemically heterogenous substances selectively inhibit the flow of Ca2+ ions through the calcium-conducting channels. The possible involvement of brain D2-dopamine receptor modulation in chronic treatment with verapamil, nicardipine and cinnarizine was investigated in rats. None of the drugs modified the affinity constant, but nicardipine and cinnarizine increased significantly the number of D2 binding sites. These results confirm the possible association of calcium antagonist receptors with selected synaptic areas and their different modulation related to their therapeutic relevance.