CUTANEOUS VASODILATION TO ACETYLCHOLINE IN PATIENTS WITH ESSENTIAL-HYPERTENSION

Endothelium-dependent vasodilation is reduced in the forearm of patien ts with essential hypertension. To evaluate whether endothelium-depend ent vasodilation is also reduced in the skin microcirculation of patie nts with essential hypertension, we evaluated the effect of acetylchol ine, an endothelium-dependent vasodilator, and sodium nitroprusside, a n endothelium-independent vasodilator, on cutaneous and total forearm blood flow in normotensive subjects (n = 8) and matched patients with essential hypertension (n = 9). We infused acetylcholine (0.15, 0.45, 1.5, 4.5, and 15 mu g/100 ml forearm tissue/min) and sodium nitropruss ide (1, 2, and 4 mu g/100 ml forearm tissue/min) into the brachial art ery, and we measured cutaneous blood flow (laser Doppler flowmeter) an d muscle blood flow (strain-gauge venous plethysmography) modification s. Both the cutaneous and muscle blood flow increases induced by acety lcholine were reduced in patients with essential hypertension as compa red with normotensive controls, whereas the skin and muscle vasodilati on induced by sodium nitroprusside was similar in the two groups of pa tients. These data confirm the impairment of endothelium-dependent vas odilation in the muscle vascular bed of patients with essential hypert ension and demonstrate the presence of endothelial dysfunction in skin microcirculation.