突触后细胞电活动促进突触发育的条件

突触在发育过程中体现出极大的可塑性，突触的简单形式：神经肌肉接点（Ｎｅｕｒｏｍｕｓｃｕｌａｒｊｕｎｃｔｉｏｎ，ＮＭＪ）在发育中的自发电活动的规率性变化常用来代征其突触塑造发育的程度．利用膜片钳技术对爪蟾胚胎ＮＭＪ突触后肌肉细胞进行全细胞电流钳制，并施予高频阈上电刺激可诱发ＮＭＪ处自发电活动的增强。深入的研究表明这种增强来自反复的去极化过程而不是单纯的膜电位升高；这种增强只有在施予电刺激的数目，频率，幅度到达一定程度才能诱发；Ｃｄ２＋胞外灌流实验提示Ｃａ２＋在肌细胞内的激增与这种增强有关。

CONDITION OF FACILITIVE EFFECT FROM POSTSYNAPTIC CELL ON DEVELOPMENT OF SYNAPSE

There is great potential in plasticity during the developing synapse. Patch Clamp Technique was employed to study the development of neuromuscular junction(NMJ) from the embryo of Xenopus. Whole - Cell current clamp record shows the High frequency electric activity of postsynaptic cell may lead to the presynaptic potentiation. This kind of Postsynaptic electric activity derived potentiation(PADP) could not occur unless the conditions of the stimulus, such as frequency, threshold, and time meet certain requirement.The existence of Cd2 prevents the occurrence of PADP which suggest that the sudden increase of the intracellular concentration of Ca2 play the main role in PADP.