A comparison of the effects of prazosin and hydrallazine on blood pressure, heart rate and plasma renin activity in conscious renal hypertensive dogs

PRAZOSIN DOES NOT ALTER CANINE RENIN RELEASE IN RESPONSE TO SYSTEMIC HYPOTENSION OR INTRARENAL ISOPRENALINE AND PROSTAGLANDIN I2 INFUSION

“…Prazosin has been reported to be a novel antihypertensive drug devoid of the acute reflex tachycardia and renin release (Massingham & Hayden, 1975;Graham et al, 1976;Wood et al, 1976). However, our findings do not substantiate this claim.…”

“…Similarly, Wood & Lee (1974) described a significant fall in plasma renin activity by day four in genetically hypertensive rats given prazosin, 25 mg/kg, daily. Massingham & Hayden (1975) found that prazosin (0.1 mg/kg i.v.) in conscious renal hypertensive dogs produced no significant acute change in heart rate or plasma renin activity.…”

“…Prazosin is reported to differ from other directly acting vasodilators by producing a reduction of arterial pressure without invoking a reflex tachycardia and renin release (Massingham & Hayden, 1975; Graham, Muir & Hayes, 1976;Wood, Bolli & Simpson, 1976). The purpose of this study was to elucidate the mechanism of the presumed inhibition of renin release by determining the effect of prazosin on the renin release elicited by the f-adrenoceptor agonist, isoprenaline and by prostaglandin I2 (PGI2).…”

Studies on the clinical pharmacology of prazosin. I: Cardiovascular, catecholamine and endocrine changes following a single dose.

“…Although it has previously been reported that hypotension produced by prazosin is not associated with an increased release of renin, (Massingham & Hayden, 1975;Bolli et al, 1976;Hayes et al, 1976;Koshy et al, 1977) our results indicate that there are large increases in standing PRA after prazosin administration at prazosin concentrations in the range which is achieved clinically. As in the case of heart rate changes, the discrepancy between renin data presented here and that reported earlier probably finds its origin in methodological differences.…”

The Effect of Prazosin on the Guinea‐pig Ileum

“…Similarly, unlike conventional a-adrenoceptor blocking agents, prazosin does not cause tachycardia or renin release in dogs (Constantine, McShane, Scriabine & Hess, 1973;Massingham & Hayden, 1975).…”