Fig. 1. Effects of propofol on phenylephrine-induced contraction of canine pulmonary arterial rings with or without endothelium (n = 7 each). Tension changes are expressed as a percentage of the contraction to phenylephrine (PE). Propofol potentiated (* P < 0.05) phenylephrine-induced contraction. Removal of endothelium did not affect the contractile response to propofol.