本態性高血圧の血小板凝集能におよぼすＢｕｎａｚｏｓｉｎの影響

Abstract

The purpose of the present study in to clarify the effect of bunazosin on platelet aggregation in the patients with essential hypertension.In vitro, the effects of 10-3-10-5M bunazosin on platelet aggregations induced by ADP, epinephrine and A23187 were studied in untreated patients with essential hypertension. The concentration of 10-3-10-4M bunazosin inhibited the platelet aggregations.Before this oral administration of bunazosin study, the patients were treated with other antihypertensive drugs for 10±7 (M±SD) weeks. Platelet aggregation (Born's method) induced by 4.6μM ADP and 5.0μM epinephrine and whole blood aggregation (Impedance method) induced by 10μM ADP and 5.0μg/ml collagen were measured in 14 patients with essential hypertension before and after administration of 1.5mg/day or 3.0mg/day for 6±4 (M±SD) weeks. Blood pressure and heart rate were measured before and after administration of bunazosin. Platelet aggregation induced by both 4.6μM ADP and 5.0μM epinephrine had a tendency to decrease and whole blood aggregation induced by both 10μM ADP and 5.0μg/ml collagen was significantly decreased (p<0.05) after administration of bunazosin. Heart rate and systolic blood pressure were not significantly changed after administration of bunazosin in the patients treated with other drugs. On the other hand, diastolic blood pressure was significantly decreased (p<0.05) after administration of bunazosin in the same patients.The present results suggest that the inhibitory effect of bunazosin on platelet aggregation may be not due to the block of α2 receptor but the inhibition of cytoplasmic calcium increase relating to the platelet activation in essential hypertension.