P2嘌呤受体激动剂对血管平滑肌BKCa通道作用机制探究.docVIP

P2嘌呤受体激动剂对血管平滑肌BKCa通道作用机制探究 　 作者：潘雪 汪晓凯 曾晓容 杨艳 蔡芳 李向楠 【摘要】 目的 探讨P2嘌呤受体激动剂对血管平滑肌大电导钙激活钾通道（BKCa)作用机制。方法 应用全细胞穿孔膜片钳记录技术，观察UTP对猪冠状动脉平滑肌细胞膜上BKCa介导的自发性瞬时外向钾电流（STOCs）的作用，并比较ATP与UTP对STOCs作用的强弱；以及磷脂酶C（PLC）的特异性阻断剂U73122预处理细胞后，UTP和ATP对STOCs的作用。结果 ①5～100 μmol/L的UTP可浓度依赖性的增加STOCs的幅度与频率，比较50 μmol/L的UTP和ATP对STOCs作用，二者无明显差异；②5 μmol/L的U73122处理细胞后50 μmol/L UTP和ATP无法激活STOCs，〔(22.76±6.43) pA，(0.222 7±0.097 7) Hz vs (23.28±8.43) pA，(0.195 3±0.061) Hz，n=7,Pgt;0.05；(23.21±7.87) pA，(0.243±0.087 6) Hz vs (24.38±9.21) pA，(0.216 2±0.075) Hz，n=6，Pgt;0.05〕。 结论 ATP和UTP可通过PLC途径激活猪冠状动脉平滑肌上的STOCs，UTP对其激活作用具有浓度依赖性，二者的激活效应无明显差异。 【关键词】 大电导钙激活钾通道；自发性瞬时外向钾电流；磷脂酶C； 三磷酸腺苷；三磷酸尿苷；穿孔膜片钳技术 【Abstract】 Objective To investigate the effects of P2 purinergic receptor agonists on large conductance calciumactivated potassium channels of vascular smooth muscle.Methods Perforatedpatch configuration of patchclamp technique was used to observe the effects of UTP and ATP on STOCs of porcine coronary smooth muscle cells as well as the effects after the cells were treated by phospholipase C( PLC) inhibitor. The effects of UTP and ATP on STOCs were compared. The cellular signal transduction mechanism of UTP and ATP effects on STOCs of porcine coronary smooth muscle cells were observed. Results ①UTP(5～100 μmol/L) significantly increased STOCs amplitude and frequency in a dosedependent manner. The effects of UTP and ATP on STOCs had no difference. ②When the cells were treated by phospholipase C (PLC) inhibitor U73122(5 μmol/L), 50 μmol/L UTP and ATP did not increase STOCs amplitude and frequency 〔(22.76±6.43) pA, (0.222 7±0.097 7) Hz vs (23.28±8.43) pA，(0.195 3±0.061) Hz, n=7, P＞0.05；(23.21±7.87) pA, (0.243±0.087 6) Hz vs (24.38±9.21) pA, (0.216 2±0.075) Hz, n=6, P＞0.05〕. Conclusions UTP activates STOCs of porcine coronary smooth muscle cells through the PLC pathway, and increases STOCs amplitude and frequency in a dosedependent manner, the effects of UTP and ATP on STOCs have no difference. 【Key words】 BKCa; Spont