ABSTRACT
Objective To investigate the ionic mechanism of remifentanil-induced vaso-relaxation by recording calcium-activated K~+-currents(IKCa)in human arterial smooth muscle cells(MASMCs).Methods Human MASMCs were obtained freshly by the method of enzymolysis.IKCa were separated with 4-AP 5 mmol?L~(-1) and recorded by the whole-cell voltage-clamped technique.The effects of remifentanil(1.2,4.8,19.4 mmol?L~(-1))on amplitude and threshold of activation for IKCa were assessed.Results Remifentanil significantly increased IKCa and had no effect on the threshold of activation for IKCa as compared with the control group(P＜0.05 or 0.01),and the IKCa returned to the baseline level after remifentanil was washed out.Conclusion Remifentanil produces vasodilation by activating IKCa in MASMCs.