目的:观察Rho-激酶、PKC、PKG对失血性休克大鼠血管钙敏感性的调控作用。方法:取失血性休克大鼠肠系膜上动脉,利用离体血管环张力测定技术,用去极化状态下(120mmol/LK^+)血管环对梯度浓度Ca^2+的收缩力反映钙敏感性,观察Rho-激酶激动剂血管紧张素Ⅱ(Ans-Ⅱ)、Rho-激酶抑制剂fasudil、PKC激动剂PMA、PKC拮抗剂staurosporine、PKG激动剂8Br-cGMP和PKG拮抗剂KT-5823对失血性休克血管钙敏感性的影响。结果:Ans-Ⅱ、PMA、KT-5823可增高失血性休克血管的钙敏感性,表现为Ca^2+的量效曲线明显左移,在Ca^2+(3×10^-2mol/L)水平,Emax分别为0.630g/mg、0.595g/mg、0.624g/mg,均明显高于休克组的0.377g/mg(P〈0.05,P〈0.01);fasudil、staurosporine、8Br-cGMP可降低失血性休克血管的钙敏感性,表现为Ca^2+的量效曲线明显右移,在Ca^2+(3×10^-2 mol/L)水平,Emax分别为0.242g/ms、0.230g/ms、0.256g/ms,均显著低于休克组(P〈0.05,P〈0.01)。结论:Rho-激酶、PKC、PKG对失血性休克大鼠血管钙敏感性有调节作用,Rho-激酶、PKC可上调钙敏感性,PKG可下调钙敏感性。
AIM: To observe the regulatory effects of Rho - kinase, PKC and PKG on calcium semitivity of vascular smooth muscle in hemorrhagic shock in rats. METHODS: The superior mesenteric artery (SMA) from hemorrhagic shock model of rat was adopted to assay the calcium sensitivity via observing the contraction initiated by Ca^2+ under depolarizing conditions (120 mmol/L K^+) with isolated organ perfusion system. Rho - kinase agonist Ang -Ⅱ and inhibitor fasudil, PKC agonist PMA and inhibitor staurosporine, PKG agonist 8Br - cGMP and inhibitor KT - 5823 were used as tool .agents to study the regulatory effect of Rho - kinase, PKC and PKG on the calcium semitivity of SMA following shock. RESULTS: Ang-Ⅱ , PMA and KT- 5823 improved the calcium sensitivity of SMA and made the cumulative dose - response curve of SMA to Ca^2+ shift to the left, their Emax of Ca^2+ (at 3 × 10^-2 mol/L) was 0.630 g/mg, 0.595 g/mg and 0.624 g/mg, respectively, which were all higher than that in shock control (0.377 g/mg) ( P 〈 0.05, P 〈 0.01). Fasudil, staurosporine and 8Br - cGMP delimitated the calcium sensitivity of SMA and made the cumulative dose - response curve of Ca^2+ shift to the right, their Emax at 3 × 10^-2 mol/L of Ca^2+ was 0.242 g/mg, 0.230 g/mg and 0.256 g/mg, respectively, which were all lower than that in shock control (0.377 g/mg) ( P 〈 0.05, P 〈 0.01 ). CONCLUSION: Rho-kinase, PKC, PKG play important roles in the regulation of calcium sensitivity of vascular smooth muscle in hemorrhagic shock.