电极位置和距离对蟾蜍坐骨神经干动作电位的影响

目的 研究“电极”与地线相互之间的位置和“电极”之间的距离对蟾蜍坐骨神经干动作电位的影响.方法 制备坐骨神经干标本,观察“电极”与地线之间相互的位置和 “电极”之间的距离对动作电位的影响.结果 刺激电极、引导电极位于地线的两侧,能引导出神经干动作电位、且刺激伪迹较小,反之则引导不到动作电位;2个刺激电极之间的距离主要影响动作电位的波形;2个引导电极之间距离对双相动作电位负相波的波宽影响不明显而对波幅影响明显,正相波的波幅变化不明显而波宽变化较大.结论 刺激电极、引导电极应位于地线的两侧,地线应尽量远离刺激电极、靠近引导电极;2个刺激电极之间的距离和2个引导电极之间的距离均应＜1 cm.

Effects of the arrangement of electrodes and earthing line and the width of electrodes on the action potential of sciatic nerve in toads

Objective To study the effects of the relative position between the electrodes and earthing line and the width of the electrodes, on the action potential of sciatic nerve. Methods Isolated toad sciatic nerve cord was prepared to investigate the effects of different positions between the electrodes and earthing line and the distance between the two poles of the electrodes, on the characters of the action potential. Results When the earthing line was placed between the stimulating electrode and leading electrode, the action potential of sciatic nerve with less feint simulation could be recorded. Contrarily, the action potential could not be led if the eleetodes were placed on the same side of the earthing line. The width or the distances between the two poles of the stimulating electrode affected the shape of the action potential, affecting the amplitude, not the width, of the negative phase of the biphasic action potential, but only the width, not the amplitude, of its positive phase.Conclusion In order to succeed in viewing the action potential elicited, the earthing line should be placed in between the stimulating electrode and the leading electrode, with the leading electrode closer to the earthing line than the stimulating electrode. Besides, the distance between the two poles of the stimulating electrode and that of the leading electrode should be less than 1 cm.