瑞芬太尼对人肠系膜小动脉平滑肌细胞钙激活钾电流的影响

Effect of remifentanil on calcium-activated potassium currents in human mesenteric arterial smooth muscle cells

目的观察瑞芬太尼对人肠系膜小动脉平滑肌细胞钙激活钾电流(IKCa)的影响,探讨其扩张血管的作用机制。方法用二步酶消化法急性分离人肠系膜小动脉平滑肌细胞,以细胞内离钙、细胞外低钙及细胞外液中加入5mol/L 4-AP分离IKCa,采用全细胞膜片钳技术,观察不同浓度瑞芬太尼(1.2、4.8、19.4 nmol·L^(-1))在不同指令电压下IKCa的变化,并计算激活电压。结果三种浓度瑞芬太尼均可使IKCa增加(P＜0.05或0.01),细胞外液洗脱后IKCa可恢复至给药前水平,但不改变激活电压(P＞0.05)。结论瑞芬太尼激活人肠系膜动脉平滑肌细胞钙激活钾通道,产生扩张血管作用。

Objective To investigate the ionic mechanism of remifentanil-induced vaso-relaxation by recording calciumactivated 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-ceU 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.