Alpha-Adrenoceptors, Adrenaline, and Exaggerated Vasoconstrictor Response to Stress in Essential Hypertension

¹ Department of Medicine and Department of Research, University Hospital, Basel, Switzerland

Stressful sympathetic stimulation by cold pressor test in patients with essential hypertension results in an exaggerated response of the already elevated plasma adrenaline, heart rate, blood pressure, and -adrenoceptor-mediated vasoconstriction when compared with normotensive subjects. The stress-induced increase in adrenaline was correlated with the attendant increase in blood pressure. The stress-induced reduction in forearm flow was reversed during infusion of the postjunctional ₁-adrenoceptor blocker prazosin. Therefore, enhanced responses to sympathetic stress, as reflected and perhaps caused by an exaggerated rise in plasma adrenaline, may contribute to an increased ₁-adrenoceptor-mediated vasoconstriction in essential hypertension.