白杨素对大鼠离体肾动脉的舒张作用

目的研究白杨素对大鼠离体肾动脉的舒张作用及其机制是否涉及抑制肾动脉血管平滑肌细胞L-型电压依赖性钙通道。方法利用微血管张力记录仪(DMT)观察白杨素对预收缩大鼠肾动脉血管环的肌源性反应;利用全细胞膜片钳电生理学实验方法,观察白杨素对大鼠离体肾动脉血管平滑肌细胞L-型电压依赖性钙电流的作用。结果 1白杨素浓度依赖性的舒张60 mmol/L KCl或10-5 mol/L去氧肾上腺素(PE)预收缩的大鼠肾动脉血管环,其最大舒张幅度分别为88.99%和67.47%,RC50值分别为26.25μmol/L和51.68μmol/L。2白杨素(浓度为RC50值)可抑制大鼠肾动脉血管平滑肌细胞L-型电压依赖性钙电流,使其I-V曲线非平行上移;给予0 mV单电压刺激时,白杨素(浓度为RC50值)使大鼠肾动脉血管平滑肌细胞L-型电压依赖性钙电流值降低45.43%。结论 1白杨素浓度依赖性舒张60 mmol/L KCl或10-5 mol/L PE预收缩的大鼠肾动脉血管环;2白杨素抑制大鼠肾动脉血管平滑肌细胞L-型电压依赖性钙电流,使其I-V曲线非平行上移。

Vasodialatory effects of Chrysin on ex-vivo rat renal artery

Objective To investigate the vasodilatory effects of chrysin on ex-vivo rat renal artery and to deter-mine the association with L-type voltage-dependent calcium channel in the arterial smooth muscle cells. Methods By utilizing the DMT microvessle tension recorder, we assessed the muscular responses of rat renal arterial ring to chrysin. Whole-cell membrane clamp was employed to determine the electrophysiology properties of the arterial smooth muscle cells. This allowed the assessment of the effects of chrysin on arterial smooth muscle cell L-type volt-age-dependent calcium channel-mediate currents in rats in vitro. Results Chrysin dilated the renal arterial ring pre-treated with 60 mmol/L KCl or 10-5 mol/L PE in a concentration-dependent fashion. The maximal magnitude of dilation was 88.99%and 67.47%, corresponding to the RC50 of 26.25 μmol/L and 51.68 μmol/L. Chrysin administered at the concentration of the RC50 abolished the renal arterial smooth muscle cell L-type voltage-dependent calcium channel-mediated current and resulted in a non-linear up-shift of the I-V curve. When stimulated with electric voltage of 0 mV, there was a reduction of 45.43%in this current. Conclusion Chrysin dilates the renal arterial ring pre-treated with 60 mmol/L KCl or 10-5 mol/L PE in a concentration-dependent fashion. Chrysin, when administered at the con-centration of the RC50, abolishes the renal arterial smooth muscle cell L-type voltage-dependent calcium channel-me-diated current and results in a non-linear up-shift of the I-V curve.