Effects of propofol on vascular smooth muscle function in isolated rat aorta.

This study was undertaken to determine the direct actions of propofol, and whether propofol exerts any action on basal endothelium-derived relaxing factor release and vasodilator effect of acetylcholine on phenylephrine-induced contractile responses in isolated rat aortic rings. This compound is known to produce a fall in blood pressure in man and animals, and it has been suggested that the hypotension may result from a direct vasodilator action on the veins and arterioles. In this study, propofol did not induce any contractile response in aortic rings at various concentrations (10(-8)-10(-4) M). Propofol did not significantly alter phenylephrine-induced contractions at lower concentrations (10(-8)-10(-6) M) but at higher concentrations (10(-5)-10(-4) M) the depression caused by propofol was significant in both endothelium-intact and -denuded rings. Pretreatment of the endothelium-intact rings with propofol (10(-6) and 10(-5) M) produced a reduction in the relaxant effect of acetylcholine. The results obtained in this study demonstrate that clinically relevant concentrations of propofol (10(-6) M or less) have no direct vasodilator effects and that it reduces endothelium-dependent relaxation to acetylcholine.