蟾蜍坐骨神经复合动作电位相对不应期的特征

背景神经纤维疾病的患者经常被推荐做复合动作电位相对不应期的测定,但其在不同刺激条件下的特性始终并未完全证实.目的通过蟾蜍坐骨神经复合动作电位的实验,更加全面地阐述复合动作电位相对不应期爆发动作电位的特点.设计随机非对照的实验研究.地点和对象由首都医科大学实验动物中心提供的6只蟾蜍,在同一生理学实验室被处死来做实验.干预以不同的刺激强度和组合方式刺激神经.主要观察指标用NSA-Ⅲ医学信号处理系统记录相对不应期发生动作电位的幅度.结果在相对不应期的同一时刻,较强的刺激会引起较大幅度的复合动作电位,并且在同样的刺激强度下,不会产生太大变化.结论在同一时期对相对不应期的刺激可引起不同阈值的神经纤维不同概率性的兴奋,但它们可以固定的概率性叠加,以形成稳定的动作电位.此外,神经干中A类神经纤维的最短绝对不应期可以通过足够强的刺激来测定.

Characteristics of therelative refractory period of compound active potential of sciatic stem in toads

BACKGROUND: The measure of "relative refractory period of compound action potential" is commonly recommended for patients with nervous fiber diseases. But its characteristics with different intensities of stimulus have not been completely proved.OBJECTIVE: To illustrate the characteristics of action potential occurring in "relative refractory period of compound action potential" from the experiment of compound action potential of sciatic stem in toads.DESIGN: A randomly uncontrolled trial study.SETTING and MATERIALS: Six toads were provided by the Experimental Animal Center of Capital University of Medical Sciences and were killed for experiment at the same physiology laboratory.INTERVENTIONS: The sciatic stems were stimulated with different intensities and combinations.MAIN OUTCOME MEASURES: The amplitudes of action potential occurring in relative refractory period were recorded by NSA-Ⅲ medical signal processing system.RESULTS: The higher extent of compound action potentials could be caused by stronger stimulations at the same point of relative refractory period, all of which were almost unchangeable with the same stimulus intensity.CONCLUSION: The stimulation in relative refractory period can cause the action potentials of the nerves, whose thresholds are different at different probabilities, but they can be added according to the same probability to form the stable extent of compound action potentials at the same intervat. On the other hand, the shortest absolute refractory period of category A nerves of the stem can be measured by enough strong intension of stimulation.