Fedorov V V
Neirofiziologiia. 1987;19(1):120-9.
The miniature end-plate currents (MEPCs), miniature postjunctional currents (MPJCs) and mean values of life-time of open ionic channels (tau chan) were compared in experiments on fast and tonic muscle fibres. The rise-time and decay-time constants of MPJCs in tonic fibres were 2.5 and 4-5 times (respectively) longer than those of MEPCs in fast fibres; tau chan in tonic synapses was 2.2 times higher than in fast ones. Inhibition of AChE induced more pronounced prolongation of MEPCs (4.4 times) than MPJCs (1.8 times). As a result, the difference between the time decay of MPJCs and MEPCs reduced to 1.6 times. Thus, a more prolonged decay of MPJCs in tonic fibres in comparison with MEPCs in fast fibres was due to a larger value of tau chan and lower activity of AChE, that favours repetitive interaction between ACh-molecules and choline receptors causing prolongation of the decay of the synaptic response. The time course of MEPCs and tau chan in skeletal slow-twitch muscle fibres was significantly shorter than those in extraocular tonic muscle fibres.
在针对快肌纤维和张力性肌纤维的实验中，对微小终板电流（MEPCs）、微小接头后电流（MPJCs）以及开放离子通道寿命的平均值（tau chan）进行了比较。张力性纤维中MPJCs的上升时间常数和衰减时间常数分别比快肌纤维中MEPCs的长2.5倍和4 - 5倍；张力性突触中的tau chan比快肌纤维突触中的高2.2倍。乙酰胆碱酯酶（AChE）的抑制对MEPCs的延长作用（4.4倍）比对MPJCs的延长作用（1.8倍）更显著。结果，MPJCs和MEPCs的时间衰减差异缩小至1.6倍。因此，与快肌纤维中的MEPCs相比，张力性纤维中MPJCs的衰减时间更长是由于tau chan值更大以及AChE活性较低，这有利于乙酰胆碱（ACh）分子与胆碱受体之间的重复相互作用，从而导致突触反应衰减时间延长。骨骼肌慢肌纤维中MEPCs的时间进程和tau chan明显短于眼外肌张力性肌纤维中的相应指标。
