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出生后心率变慢的窦房结调控机制

杨智昉, 李慈珍, 李倩, 汪锡金, 刘远谋

上海第二医科大学生理教研室.上海(200025)

摘要

用离体兔心灌流、窦房结细胞动作电位记录、膜片钳实验和放射免疫分析细胞内cAMP含量等方法，研究不同周龄组兔心自律性变慢的心脏内源性因素。实验结果提示，离体心脏和窦房结标本在没有神经体液因素影响的情况下也有随周龄增长而自律性变慢的现象。进一步的实验提示，这可能是由于窦房结细胞内cAMP含量下降，使起搏离子流I_f的阈电位向负方向移位，造成窦房结细胞4期自动除极速率降低，最后导致心率变慢。上述结果表明，成长过程中的心率变慢，除有神经体泫因素影响我，窦房结细胞本身自律性的改变也起了一定作用。

关键词： 膜片钳; 窦房结; 起搏离子流; 心率

The sinus node itself also plays a role in heart rate slowing down during postnatal development

Yang Zhifang, Li Cizhen, Li Qian, Wang Xijin, Liu Yuanmou

Department of Physiology, Shanghai Second medical University.Shanghai(200025)

Abstract

The slowing down mechanism of heart rate during growth of the body after birth was studied in isolated rabbit heart and sinus node (SN) preparation with langendorff perfusion method, conventional was also used to measure the concentration of cAMP within SN cells. The results indicate that without the influence of nervous and humoral factors, the spontaneous heart rate would also become slower as the rabbit grew older, which is due to the decrease of spontaneous depolarized rate of phase 4 in SN cells. The negative-directed shift of the threshold potential of I_f and the decrease in cAMP concentration within SN cells may be responsible for the phenomenon. The results obtained suggest that besides the nervous and humoral factors which influence the heart rate, the changes in automaticity of SN cell itself may take part in the slowing down process as the body grows up.

Key words: Patch clamp;Sinus node;Pacemaker current;Heart rate

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引用本文：

杨智昉, 李慈珍, 李倩, 汪锡金, 刘远谋. 出生后心率变慢的窦房结调控机制[J]. 生理学报 2002; 54 (4): .

Yang Zhifang, Li Cizhen, Li Qian, Wang Xijin, Liu Yuanmou. The sinus node itself also plays a role in heart rate slowing down during postnatal development. Acta Physiol Sin 2002; 54 (4): (in Chinese with English abstract).