Effect of captopril on platelet cytosolic [Ca2+]i and plasma TXA2/PGI2 in renovascular hypertensive rats

AIM: To study the effect of captopril (Cap) on platelet cytosolic free calcium concentration ([Ca2+]i), platelet aggregation (PAg), and plasma TXA2/PGI2 ratio in the renovascular hypertensive rats. METHODS: Blood pressure was measured once a week by tail-cuff microphonic manometer. Platelet [Ca2+]i was measured by Fura 2-AM. Plasma angiotensin II (Ang), thromboxane A2 (TXA2), and prostacycline (PGI2) were measured by radioimmunoassay. RESULTS: Platelet [Ca2+]i and PAg increased (P < 0.01), while plasma Ang and TXA2/PGI2 ratio elevated (P < 0.05) in the renovascular hypertensive rats; platelet [Ca2+]i and plasma TXA2/PGI2 ratio reduced markedly after i.g. Cap 100 mg.kg-1.d-1 compared with saline for 2 wk. CONCLUSION: The altered TXA2/PGI2 after Cap treatment contributed to the improvement of the platelet [Ca2+]i and PAg.