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Effects of calcitonin gene-related peptide on repolarization process in isolated guinea-pig atrial myocardium at the physiological temperature

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Author:: No author available

Journal Title:: ACTA PHYSIOLOGICA SINICA

Issue:: 2

DOI:: 10.3321/j.issn:0371-0874.2002.02.015

Key Word:: 降钙素基因相关肽;动作电位;心房肌细胞;豚鼠

Abstract：实验应用常规微电极方法研究了在生理温度下(36.5±0.5℃)降钙素基因相关肽(calcitonin gene-related peptide,CGRP)对豚鼠心房肌细胞复极过程的影响及其与钾电流的关系.结果表明:(1)CGRP(16 nmol/L)可拮抗由钾通道阻断剂BaCl2、 4-AP引起的动作电位时间延长.(2)CGRP(16 nmol/L)能够增加细胞外高钾(18.5 mmol/L)条件下心房肌慢反应动作电位的APA和Vmax,并缩短传导时间.(3)CGRP(16 nmol/L)能减弱甚至消除因并用CsCl (5 mmol/L)和无钾灌流液诱发的触发活动.(4)CGRP对动作电位复极过程的作用因温度条件而异.在生理温度下,CGRP(5、16和50 nmol/L)能够使动作电位平台抬高,缩短动作电位复极化20%、50%和90%时程.其中,对动作电位复极化20%、50%时程的作用呈剂量依赖性.而在室温下(25.5±2.1℃),CGRP使动作电位复极化20%、50%和90%时程延长.上述结果提示,CGRP对心房肌细胞具有多重电生理效应,其中生理温度下CGRP对钾电流的促进作用在动作电位的改变中占重要地位,今后有必要进一步研究CGRP对各种钾通道的作用.

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