去甲肾上腺素对豚鼠乳头肌动作电位的影响

Effects of Norepinephrine on Action Potentials of Guinea Pig Papillary Muscles

目的:研究去甲肾上腺素(NE)对豚鼠心室乳头肌动作电位的影响。方法:采用玻璃微电极细胞内引导技术,记录离体豚鼠心室乳头肌动作电位,在此基础上,观察NE对豚鼠心室乳头肌动作电位的影响及酚妥拉明的拮抗作用。结果:100μmol/L NE可使乳头肌动作电位时程(APD)明显延长(P<0.05),动作电位复极50%和90%时间(APD50and APD90)明显延长(P<0.05)。而100μmol/L酚妥拉明可使延长的APD、APD50、APD90明显恢复。结论:去甲肾上腺素可明显延长豚鼠心室乳头肌动作电位时程,而酚妥拉明可阻断此效应。

Objective： This study was designed to investigate the effects of norepinephine（NE） on the action potentials of guinea pig papillary mucsles. Methods： By using conventional intracellular microelectrode technique, the action potentials were recorded. The the electrophysiologieal features and regularities of papilla- ry mucsles for NE and phentolamine were investigate. Electrophysiological parameters examined were： resting potentials （RP）, amplitude of action potential （APA）, maximal rate of depolarization （Vmax）, 50% and 90% of duration of action potential （APD50 and APD90）, duration of action potential （APD）. Results：Perfusion with 100ttmol/L NE resulted in a significant prolonging in APD （P〈0.01）, APD90 （P〈0.05）, APD50 （P〈 0. 01 ） ;phentolamine （100μmol/L）completely blocked the effects of NE （100μmol/L） on APD, APD50,APD90 of guinea pig papillary muscles. Conclusion： NE can significantly lengthen the duration of action potentials of guinea pig papillary muscles and phentolamine could block the effects of NE.