槲皮素舒张大鼠离体肾动脉及其与L-型电压依赖性钙通道和蛋白激酶C的关系

Vasodilation of quercetin on rat renal artery and the relationship with L-type voltage-gated Ca^(2+) channels and protein kinase C

为了观察槲皮素对大鼠离体肾动脉的舒张作用,并探讨该作用与蛋白激酶C(protein kinase C,PKC)的关系,本研究采用血管张力测定仪记录大鼠肾动脉肌张力变化,用膜片钳全细胞记录方式记录大鼠肾动脉血管平滑肌细胞(vascular smooth muscle cell,VSMC)L-型电压依赖性钙通道(L-type voltage-gated Ca^(2+) channels,LVGC)电流。实验结果显示,槲皮素能够舒张60 mmol/L KCl或1×10^(-5) mol/L苯肾上腺素(phenylephrine,PE)预收缩的大鼠肾动脉,其最大舒张百分比分别为(84.53±7.35)%和(76.42±4.63)%;血管内皮完整组和去内皮组肾动脉相比,槲皮素对预收缩肾动脉的最大舒张百分比没有显著性差异;预孵育PKC特异性抑制剂C6303可使槲皮素对肾动脉的最大舒张幅度降低,与未孵育C6303组相比具有统计学差异(P<0.05);离体大鼠肾动脉VSMC的正常LVGC尖峰电流密度为(23.17±1.33)pA/pF,10μmol/L槲皮素可以降低其电流密度到(10.46±1.35)pA/pF,其抑制百分比为54.86%,1μmol/L C6303可部分逆转槲皮素对LVGC电流的降低幅度,其抑制百分比为62.08%(P<0.05)。上述实验结果提示,槲皮素可舒张大鼠离体肾动脉,该作用具有浓度依赖性且不受内皮影响,可能与抑制LVGC和激活PKC有关。

To investigate the diastolic function of quercetin on rat renal artery in vitro and its mechanism, the tension of rat renal artery was recorded by multi myograph system, and the L-type voltage-gated Ca2＋ channels （LVGC） current was recorded by whole-cell patch clamp technique. Quercetin produced relaxation effect on rat renal artery pre-contracted by 60 mmol/L KCl or 1 × 10？5 mol/L phenylephrine, and the maximal diastolic percentage was （84.53 ± 7.35）% or （76.42 ± 4.63）%. There was no statistical difference in the maximal diastolic percentage between endothelium-intact and endothelium-denuded groups. Pre-incubation of protein kinase C （PKC） inhibitor C6303 inhibited the maximal diastolic amplitude induced by quercetin. The peak current density of LVGC in rat renal artery vascular smooth muscle cells （VSMCs） was （23.17 ± 1.33） pA/pF. Quercetin （10 μmol/L） inhibited the peak current to （10.46 ± 1.35） pA/pF, and the inhibition percentage was 54.86%. C6303 （1 μmol/L） partially reversed the inhibitory effect of quercetin, and the inhibition percentage was 62.08% （P 〈 0.05）. These results suggest that quercetin can relax rat renal artery in vitro in a concentration-dependent and endothelium- independent manner. The vasodilation of quercetin may be related to inhibition of LVGC current and activation of PKC.