Direct vasoconstrictor and vasodilator effects of propofol in isolated dog arteries.

We have measured the direct effects of propofol 10(-7)-10(-4) mol litre-1 on isolated canine cerebral, coronary, mesenteric, femoral and renal arteries. In arterial strips precontracted submaximally with potassium chloride or prostaglandin F2 alpha (PGF2 alpha), propofol induced further contractions at low concentrations (10(-6)-10(-5) mol litre-1) and relaxation at high concentrations (10(-4) mol litre-1). Intrafat, which contains soya bean oil, egg phosphatide and glycerol in similar concentration to the emulsion formulation of propofol, had a small relaxant effect at a concentration corresponding to propofol 10(-4) mol litre-1. In humans, clinically relevant plasma concentrations of propofol have been reported to be 1-5 x 10(-5) mol litre-1, 97-99% of which is bound to plasma proteins. Therefore, the results obtained in this study demonstrated that clinically relevant concentrations of propofol did not have direct vasodilator effects.