On the Mechanism of the Potentiating of the Angiotensin Pressor Effect by Guanethidine and Desmethylimipramine

Abstract

The simultaneous administration of an [alpha]- and [beta]-adrenergic receptor blocking agent, such as phentolamine and nethalide, in guanethidine or desmethylimipramine pretreated cats, proves to be capable of abolishing or reducing in relation to the dose employed the norepinephrine hypertension and of reducing to almost basal values the angiotensin pressor effect potentiated by former treatment with guanethidine or desmethylimipramine. According to results obtained the Increase in the pressor responses of angiotensin brought about by guanethidine and esmethylimipramine is to be interpreted as a consequence of the potentiating of cardiovascular effects of epinephrine released from the adrenal medulla directly by the polypeptide.