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 contracti le and relaxant responses in experimental hypertension and assessed endothe lial modulation of these responses. Propofol attenuated norepinephrine-indu ced contraction of endothelium-intact and endothelium-denuded rings from bo th Wistar Tokyo (WKY) and spontaneously hypertensive rats (SHR). The effect was significantly greater in endothelium-intact aortae from SHR than in th ose from WKY rats. Propofol markedly attenuated AVP-induced contraction in aortae from both WKY and SHR. Propofol attenuation of norepinephrine contra ction was also observed in rings from both SHR and WKY rats incubated with L-NAME. Propofol attenuation of norepinephrine contraction was suppressed b y indomethacin in aortae from SHR but not in those from WKY rats. These res ults suggest that: (1) propofol attenuated vascular contraction of isolated aortae from SHR in part by a mechanism dependent on events distal to the r eceptor site (norepinephrine, arginine vasopressin); (2) the effect of prop ofol on contraction in SHR, observed in the presence of nitric oxide syntha se inhibitors but not cyclooxygenase inhibitors, was consistent with either propofol induction of vasodilating cyclooxygenase metabolites from the end othelium or propofol inhibition of vasoconstricting cyclooxygenase metaboli tes.