Giniatullin R A, Magazanik L G
Kazan State Medical University, 420012 Kazan, 49, Butlerov St., Russia.
Ross Fiziol Zh Im I M Sechenova. 1997 Mar;83(3):67-72.
Dependence of the amplitude of miniature end-plate currents on frequency of spontaneous quantal release modulated by the elevation of K+ concentration was studied in the frog voltage clamped neuromuscular junctions. A sharp increase of mEPC frequency (not less than approximately 50 per sec) was followed by an obvious fall in both their amplitude and acceleration of decay only in the presence of 3 microM prostigmine (acetylcholinesterase inhibitor) and 5 microM proadiphene, these agents promoting a desensitization of cholinergic postsynaptic membrane. Probable depletion of transmitter store is not involved in the phenomenon observed which is mainly due to the repetitive activation of the postsynaptic zones and the increase of the desensitized cholinoreceptor number.
在蛙的电压钳制神经肌肉接头处，研究了由钾离子浓度升高所调制的微小终板电流幅度对自发量子释放频率的依赖性。仅在存在3微摩尔毒扁豆碱（乙酰胆碱酯酶抑制剂）和5微摩尔普罗地芬的情况下，微小终板电流频率急剧增加（不少于约每秒50次）之后，其幅度和衰减加速才会明显下降，这些药物会促进胆碱能突触后膜的脱敏。观察到的现象并不涉及递质储备的可能耗竭，这主要是由于突触后区域的重复激活和脱敏胆碱能受体数量的增加。
