Mechanism of the hypotensive effect of prazosin.

摘要: Prazosin is a quinazoline that has long lasting hypotensive effect. To investigate the mechanisms underlying its action experiments were performed in 75 dogs anesthetized with pentobarbitone sodium. Prazosin, after i.v. injection, lowered arterial pressure without altering heart rate and venous pressure, decreased pressor responses to epinephrine, norepinephrine splanchnic nerve stimulation. Orthocarboxybenzeno-seleninic acid, an alpha-adrenoceptor blocker, antagonized effect of prazosin. Neither administration propranolol nor carotid sinus local anesthesia impaired prazosin effects. Topical application on both sinuses had no general blood pressure; intravenous it did not change hypotension caused by electrical stimulation sinuses. The depressor effects papaverine sodium nitrite enhanced It concluded this drug exerts blocking, alpha-adrenoceptors possibly relaxing vascular smooth muscle.