Fulgenzi G, Cuppini R, Bruno C
Istituto di Anatomia e Fisiologia generale Università degli studi di Urbino.
Boll Soc Ital Biol Sper. 1991 Jul;67(7):667-71.
Miniature endplate potentials (MEPPs) are regarded as the expression of release of a single quantum of acetylcholine by motor nerve endings in the muscle. Mepp frequency is dependent on the presynaptic mechanism, but MEPP amplitudes and time courses are the result of the characteristics of pre- and postsynaptic structures and of the interaction between them. After post-traumatic reinnervation of skeletal muscles, MEPP frequency increases, reaching slowly normal values. Two groups of male, Sprague Dawley rats were used: in the first group left sciatic nerve was crushed and nerve fibres were allowed to regenerate, whereas the others were regarded as controls. MEPPs were intracellularly recorded in end plates of normal and reinnervated left extensor digitorum longus muscle. MEPPs were sampled and recorded on a personal computer, and, subsequently, amplitude, rise time and half decay time were computed. At early stage after reinnervation, MEPPs showed rise times and decay times longer than normal. Afterwards, we did not find differences between mepp time courses by normal and reinnervated end plates. The possible relationships between the results and changes in acetylcholine receptor number and type, and in acetylcholinesterase activity occurring during denervation and reinnervation are discussed.
微小终板电位（MEPPs）被认为是肌肉中运动神经末梢释放单个乙酰胆碱量子的表现。微小终板电位频率取决于突触前机制，但微小终板电位的幅度和时程是突触前和突触后结构特征及其相互作用的结果。骨骼肌创伤后再支配后，微小终板电位频率增加，缓慢达到正常值。使用两组雄性Sprague Dawley大鼠：第一组左侧坐骨神经被挤压，使神经纤维再生，而另一组作为对照。在正常和再支配的左侧趾长伸肌终板内细胞记录微小终板电位。微小终板电位在个人计算机上采样和记录，随后计算幅度、上升时间和半衰期。在再支配后的早期，微小终板电位的上升时间和衰减时间比正常时长。之后，我们未发现正常终板和再支配终板的微小终板电位时程存在差异。讨论了这些结果与去神经和再支配过程中乙酰胆碱受体数量和类型以及乙酰胆碱酯酶活性变化之间的可能关系。
