CENTRAL AND PERIPHERAL CARDIOVASCULAR EFFECTS OF ALPHA-METHYLEPINEPHRINE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 227  (2) , 484-490
Abstract
Peripheral and central cardiovascular effects of (.+-.)-.alpha.-methylepinephrine (.alpha.-ME) and (.+-.)-.alpha.-methylnorepinephrine (.alpha.-MNE), 2 putative active metabolites of .alpha.-methyldopa were compared to those of (-)-epinephrine in urethane-anesthetized normotensive rats. I.v. administration of 1 .mu.g doses of .alpha.-ME (4.3 nmol) was lowered blood pressure whereas .alpha.-MNE (4.5 nmol) and (-)-epinephrine (3.0 nmol) raised blood pressure. Heart rate responses to each were opposite to the blood pressure response, consistent with reflex buffering. When administered into the cerebral ventricle (5-20 .mu.g) (15-90 nmol) and nucleus of the solitary tract (0.3-10 nmol), each catecholamine caused marked reductions in both blood pressure and heart rate. .alpha.-ME was more potent than .alpha.-MNE and the endogenous catecholamine (-)-epinephrine, in its central depressor effect. The greater potency of .alpha.-ME relative to .alpha.-MNE and (-)-epinephrine suggested that it could contribute to antihypertensive actions of .alpha.-methyldopa.