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1、136生理学报ActaPhysiologicaSinica,April25,2006,58(2):136-140http://www.actaps.com.cn研究论文温度和胞内钠、ATP及酸碱度对心室肌细胞钠钙交换电流的调节周红义，韩重阳，王晓良*中国医学科学院、中国协和医科大学药物研究所，北京100050+摘要：心肌缺血损伤过程中，胞内Na、ATP及pH都出现明显变化。钠/钙交换对心肌细胞的钙平衡起重要的调节作+用。本实验采用膜片钳全细胞记录豚鼠心室肌细胞钠/钙交换电流，研究温度和胞内Na、ATP及pH对钠/钙交换双
2、向电流的影响。结果表明，温度从22℃升至34℃，钠/钙交换电流增大约4倍，而pH值的改变对钠/钙交换双向电流没有明显的影响。在22~24℃时，同时耗竭胞内ATP和胞内酸化对钠/钙交换双向转运功能影响程度小；而在34~37℃时，同时耗竭胞内ATP和胞内酸化能抑制钠/钙交换双向电流的外向和内向成分，且内向成分抑制程度高于外向成分抑制程度。表+明同时耗竭胞内ATP和胞内酸化对钠/钙交换的作用具有温度依赖性。胞内Na超载能使钠/钙交换电流的外向成分增加，但不增加或减少内向电流(即正向转运)成分。因此，胞内酸化及耗竭胞内ATP损伤
3、细胞排钙机制和胞内钠超载通过钠/钙反向交换引起钙内流是引起心肌细胞钙超载的两个独立的重要因素。关键词：钠钙交换体；温度；钠；膜片钳技术中图分类号：R329Regulativeeffectsoftemperature,intracellularsodium,ATPandpHonIofNa/CacardiacmyocytesZHOUHong-Yi,HANChong-Yang,WANGXiao-Liang*InstituteofMateriaMedica,ChineseAcademyofMedicalSciencesandPe
4、kingUnionMedicalCollege,Beijing100050,China+2+2+Abstract:TheNa-CaexchangeisamajorpathwayforremovalofcytosolicCaincardiacmyocytes.Toexploretheeffectsof++2+temperature,intracellularNa,ATPandpHonNa-Caexchangecurrents(I)ofintactguinea-pigmyocytes,thewhole-cellpatch-N
5、a/CaclamptechniquewasusedtorecordIinisolatedguinea-pigventricularmyocytes.WefoundthatIat34ºCwasfourtimeshigherNa/CaNa/Cathanthatat22ºC.However,intracellularacidificationhadnoobviousinfluenceonbidirectionalI.At22~24ºC,intracellularATPNa/Cadepletionandintracellular
6、acidificationdidnotmarkedlyaffectbidirectionalIeither.At34~37ºC,intracellularATPdepletionandNa/CaintracellularacidificationsynergisticallyinhibitedtheoutwardandinwardcurrentsofI,andblockedtheinwardcurrentsofINa/CaNa/CamorepotentlythantheoutwardcurrentsofI.Theeffe
7、ctofATPonIistemperature-dependent.IntracellularhighersodiumNa/CaNa/CaincreasedtheoutwardcurrentsofI,howeveritdidn’tincrease,evensometimesdecreasedtheinwardcurrentsofI.TheseresultsNa/CaNa/Ca2++2+suggestthatintracellularATPdepletionandintracellularacidificationsyne
8、rgisticallyimpairCaextrusionviaforwardmodeNa-Ca2++2+exchange,andintracellularsodiumoverloadincreasesCainfluxviareversemodeNa-Caexchange,leadingtocalciumoverloa
