Arterial response to venous occlusion in normotensive and hypertensive subjects

Plethysmographic blood flow records made shortly after venous occlusion of the forearm showed a biphasic response, first vasodilator then vasoconstrictor, in both normotensive and hypertensive subjects. The vasodilator component of this response was significantly lower in hypertensive than in normotensive subjects, whereas the vasoconstrictor component was identical. The decreased vasodilator capacity of the forearm resistance vessels in hypertension may indicate structural adaptation of these vessels, while the unaltered vasoconstrictor response is against any increased myogenic activity in the vascular smooth muscle in hypertensive subjects.