Effects of propofol on vascular reactivity in isolated aortae from normotensive and spontaneously hypertensive rats

We have investigated the effects of propofol 50 mu mol litre-l on contractile and relaxant responses in experimental hypertension and assessed endothelial modulation of these responses. Propofol attenuated norepinephrine-induced contraction of endothelium-intact and endothelium-denuded rings from both Wistar Tokyo (WKY) and spontaneously hypertensive rats (SHR). The effect was significantly greater in endothelium-intact aortae from SHR than in those from WKY rats. Propofol markedly attenuated AVP-induced contraction in aortae from both WKY and SHR. Propofol attenuation of norepinephrine contraction was also observed in rings from both SHR and WKY rats incubated with L-NAME. Propofol attenuation of norepinephrine contraction was suppressed by indomethacin in aortae from SHR but not in those from WKY rats. These results suggest that: (1) propofol attenuated vascular contraction of isolated aortae from SHR in part by a mechanism dependent on events distal to the receptor site (norepinephrine, arginine vasopressin); (2) the effect of propofol on contraction in SHR, observed in the presence of nitric oxide synthase inhibitors but not cyclooxygenase inhibitors, was consistent with either propofol induction of vasodilating cyclooxygenase metabolites from the endothelium or propofol inhibition of vasoconstricting cyclooxygenase metabolites.