常氧和急性低氧下大鼠传导性肺动脉平滑肌细胞的电生理特性VIP免费

生理学报ActaPhysiologicaSinica,October25,2006,58(5):477-482http://www.actaps.com.cn477研究论文Received2005-11-21Accepted2006-07-10ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(No.30393133,30260034).*Correspondingauthor.Tel:+86-971-6142063;Fax:+86-971-6142063;E-mail:gerili@public.xn.qh.cn常氧和急性低氧下大鼠传导性肺动脉平滑肌细胞的电生理特性胡颖1，邹飞2，蔡春青2，吴航宇2，韵海霞1，陈云天1，靳国恩1，格日力1,*1青海大学高原医学研究中心，西宁810001；2南方医科大学公共卫生与热带医学学院，广州510515摘要：本文旨在研究大鼠传导性肺动脉平滑肌细胞(pulmonaryarterysmoothmusclecells,PASMCs)的电生理特征及对急性低氧的反应。用酶解法急性分离出1~2级分支的PASMCs，通过全细胞膜片钳方法研究常氧及急性低氧状况下细胞钾电流的差异，并在常氧下先后使用iBTX和4-AP阻断大电导钙激活钾离子(largeconductanceCa-activatedK+,BKCa)通道及延迟整流性钾离子(delayedrectifierK+,KDR)通道后，观察细胞钾电流特征。根据细胞的大小、形态及电生理特征可将PASMCs分为Ⅰ、Ⅱ、Ⅲ类。iBTX对Ⅰ类细胞几乎无作用，而4-AP几乎完全阻断它的钾电流；Ⅱ类细胞的钾电流在加入iBTX后大部分被抑制，其余的对4-AP敏感；Ⅲ类细胞的钾电流对iBTX及4-AP均敏感。急性低氧对三类细胞的钾电流均有不同程度的抑制，并使Ⅰ类细胞的膜电位显著升高，而Ⅱ、Ⅲ类细胞膜电位升高的程度不如Ⅰ类显著。结果表明，传导性肺动脉有3种形态及电生理特性不同的PASMCs，在急性低氧时其钾电流不同程度地受到抑制，同时静息膜电位也有不同程度去极化，这些可能参与急性低氧时传导性肺动脉舒缩反应的调节。KDR及BKCa通道在3种细胞中的比例不同可能是急性低氧对3种PASMCs影响不同的离子基础。关键词：电生理；肺动脉；平滑肌细胞；低氧；钾通道中图分类号：Q25ElectrophysiologicalstudyonratconduitpulmonaryarterysmoothmusclecellsundernormoxiaandacutehypoxiaHUYing1,ZOUFei2,CAIChun-Qing2,WUHang-Yu2,YUNHai-Xia1,CHENYun-Tian1,JINGuo-En1,GERi-Li1,*1ResearchCenterForHighAltitudeMedicineofQinghaiUniversity,Xining810001,China;2SchoolofPublicHealthandTropicalMedicine,SouthernMedicalUniversity,Guangzhou510515,ChinaAbstract:Thepresentstudywasdesignedtoinvestigatetheelectrophysiologicalcharacteristicsofratconduitpulmonaryarterysmoothmusclecells(PASMCs)andtheresponsetoacutehypoxia.PASMCsofthe1stto2ndorderbranchesintheconduitpulmonaryarterieswereobtainedbyenzymaticisolation.ThePASMCsweredividedintoacutehypoxiapreconditionedgroupandnormoxiagroup.Hypoxiasolutionswereachievedbybubblingwith5%CO2plus95%N2foratleast30minbeforecellperfusion.Potassiumcurrentswerecomparedbetweenthesetwogroupsusingwhole-cellpatchclamptechnique.ThetotaloutwardcurrentofPASMCswasmeasuredundernormoxiaconditionwheniBTX[specificblockingagentoflargeconductanceCa-activatedK+(BKCa)channel]and4-AP[specificblockingagentofdelayedrectifierK+(KDR)channel]wereaddedconsequentlyintobathsolution.PASMCswereclassifiedintothreetypesaccordingtotheirsize,shapeandelectrophysiologicalcharacteristics.TypeIcellsarethesmallestwithspindleshape,smoothsurfaceanddiscreteperinuclearbulge.TypeIIcellsshowthebiggestsizewithbanana-likeappearance.TypeIIIcellshavethesimilarsizewithtypeI,andpresentintermediaryshapebetweentypeIandtypeII.iBTXhadlittleeffectonthetotaloutwardcurrentintypeIcells,while4-APalmostcompletelyblockedit.MostofthetotaloutwardcurrentintypeIIcellswasinhibitedbyiBTX,andtheremainingwassensitiveto4-AP.IntypeIIIcells,thetotaloutwardcurrentwassensitivetobothiBTXand4-AP.Acutehypoxiareducedthecurrentinallthreetypesofcells:(1614.8±62.5)pAto(892.4±33.6)pAfortypeIcells(P<0.01);(...