细胞外低钠灌流对豚鼠心室肌细胞内钾离子活度的影响  

EFFECTSOFLOWEXTERNALSODIUMONINTRACELLULARPOTASSIUMACTIVITYINGUINEAPIGCARDIACVENTRICULARMYOCYTES

作　　者：刘北英[1] 韩大英[1] 钮伟真[1] 赵文颖 曹敬清[1] 

机构地区：[1]首都医科大学心血管生理研究室

出　　处：《中国应用生理学杂志》1996年第4期352-355,共4页Chinese Journal of Applied Physiology

摘　　要：本实验应用钾离子选择微电极观察了不同浓度的低钠对豚鼠心室肌细胞内钾离子活度（ａｉＫ）的影响。发现细胞外低钠（低［Ｎａ］ｏ）灌流引起明显的ａｉＫ下降，下降幅度随灌流液中Ｎａ＋浓度的降低而加大。Ｃｓ＋（５ｍｍｏｌ／Ｌ）及低钾（２．５ｍｍｏｌ／Ｌ）灌流均可明显减小这种ａｉＫ的下降。Ｃａ２＋通道阻断剂Ｃｄ２＋、Ｎｉ２＋、Ｍｎ２＋及Ｖｅｒａｐａｍｉｌ对此无影响；而长时间的Ｃａｆｅｉｎｅ（１０ｍｍｏｌ／Ｌ，３０ｍｉｎ）灌流可减小低钠引起的ａｉＫ下降。鉴于上述结果，我们认为：低［Ｎａ］ｏ引起的ａｉＫ下降与细胞膜钠泵活动的改变关系不大，而很可能与细胞膜对Ｋ＋的通透性及细胞膜上钙调节Ｋ＋通道的活动改变有关。Theefectsoflowsodiumsuperfusiononintracelularpotasiumactivity(aiK)wasinvestigatedwithK+ selectivemicroelectrodeinguinea pigventriculartrabeculae.AsignificantdecreaseofaiKwasobservedduringsuperfusionoflowsodium.ThedecreaseofaiKwasincreasedwithreducingper fusatesodiumconcentration.BothoflowexternalK+(2.5mmol/L)andCs+(5mmol/L)reducedthedecreaseofaiKmarkedly.TheCa2+channelblockers(Cd2+,Mn2+,Ni2+andVerapamil)didnotafectthedecreaseofaiK,whileduringlong timecafeinesuperfusion(10mmol/L,25-30min)thedecreaseofaiKwasreduced.TheaboveresultssuggestthatthedecreaseofaiKinducedbylowsodi umsuperfusionmayberelatedtomembranepermeabilitytoK+andmembraneCa2+ activatedK+channel,butunreletedtothechangeofsodiumpumpactivity.TheincreasedintracelularfreeCa+2maybederivedfromtheintracelularCa+2sources.

关 键 词：心室肌细胞 钾离子活度 低钠灌流 生理 

分 类 号：R331.31[医药卫生—人体生理学]