EFFECTS OF HALOPERIDOL AND CHLORPROMAZINE ON SMOOTH-MUSCLE CONTRACTILITY, PLATELET-AGGREGATION AND NEURONAL CALCIUM CURRENT

Effects of chlorpromazine, haloperidol (neuroleptics and calmodulin an tagonists), and verapamil on rat platelet aggregation induced by throm bin, on calcium current in snail neurones and on both tonic tension of high potassium contracture and phasic contraction of isolated guinea- pig ureter preparations were studied. Moreover, droperidol, sulpiride and prazosine effects were studied for models of phasic contractility and platelet aggregation. Sulpiride and prazosine were ineffective, ve rapamil was ineffective on platelet aggregation, while droperidol was the most potent inhibitor of platelet aggregation. These results, the similarity revealed in the blockage of neuronal calcium current by neu roleptics and verapamil, and the potent inhibitory action of haloperid ol and chlorpromazine on contractility and aggregation suggest that bo th phenothiazine and butyrophenone neuroleptics possess some propertie s of calcium antagonists and may also have intracellular sites of acti on other than calmodulin.