中文摘要：

本研究应用全细胞膜片钳技术在离体豚鼠小脑前下动脉（AICA）和肠系膜动脉（MA）的平滑肌细胞上，观察300μmol／L．18β-甘草次酸（18βGA）对微动脉平滑肌细胞膜电流的影响。结果显示：（1）18βGA能够增强微动脉平滑肌细胞外向电流，300μmol／L18βGA使AICA和MA平滑肌细胞外向电流（＋40mV）分别从234±36pA和154±25pA增强到376±41pA（n=8，P〈0．05）和348±45pA（n=11，P〈0．01）。188GA增强微动脉平滑肌细胞外向电流具有电压依赖性，18β6A主要增强0～＋40mV电压区间的激活电流，其中对＋40mV阶跃电压激活电流的作用最强。（2）300μmol／L18βGA的净电流与10mmol／L TEA和50nmol／LChTX相似，与lmmol／L 4-AP不同。预灌流10mmol／LTEA后300μmol／L 18βGA对微动脉平滑肌细胞外向电流的增强作用完全消失。上述结果提示300μmol／L18βGA能够电压依赖的增强豚鼠AICA和MA微动脉平滑肌细胞BKCa通道电流。

英文摘要：

In this study,whole-cell patch clamp recording technique was used to investigate the effect of 300 μmol/L 18β-glycyr- rhetinic acid （18βGA） on the membrane current of vascular smooth muscle cells （VSMCs） in guinea, pig anterior inferior cerebellar artery （AICA） and mesenteric artery （MA）. Results show as below： （1）18βGA could enhance the membrane current of VSMCs. 300 μmol/L 18βGA enhanced the outward current （4-40 mV） of VSMCs of A1CA andMA from 234±36 pA and 154 ±25 pA to 376141 pA（n= 8,p〈0.05） and 348±45 pA（n=11,P〈0.01） respectively. 18βGA enhanced the outward current of VSMCs in a voltage dependent way. 18βGA induced a more pronounced enhancement of the outward current from 0 to 4-40 mV,especially at 4-40 mV. （2）The net current induced by 1813GA was similar to 10 mmol/L TEA and 50 nmol/L ChTX,but not with 1 mmol/L 4AP. In the presence of 10 mmol/L TEA,/he enhancement of 18βGA on the membrane current of VSMCs totally disappeared. These results suggest that 300μmol/L 18βGA enhances the current of BKca channel of VSMCs in arterioles by voltage-dependent way in guinea pig.