THE EFFECTS OF BRETYLIUM AND GUANETHIDINE ON THE PRESSOR RESPONSES TO NORADRENALINE AND ANGIOTENSIN.

In normal human subjects the intravenous administration of bretylium and guanethidine rapidly increased the pressor response to intravenous infusions of noradrenaline, while the response to angiotensin was little or not affected. This result suggests that potentiation of noradrenaline by bretylium and guanethidine is not simply due to block of homeostatic reflexes, but is due to sensitization of arteriolar smooth muscle. But we, like others, have failed to demonstrate such an effect in man when measuring changes in blood flow during intra-arterial infusions of noradrenaline.