Benes F M, Barrnett R J
Brain Res. 1978 Jul 14;150(2):277-93. doi: 10.1016/0006-8993(78)90280-9.
The present study compares choline acetylase (ChAc) activity with morphometric determinations of synaptic vesicles at the neuromuscular junctions of frog pectoralis muscle subjected to high and low frequency stimulation in the presence or absence of NVP, a ChAc inhibitor. Muscles stimulated at 10/sec for 20 min with one hour rest, in the presence of NVP, showed an approximately 50% reduction in synthesis of Ach, and a 50--60% reduction in the numerical density of synaptic vesicles relative to controls preparations. Similar nerve muscle preparations stimulated at 2/sec for one hour without rest, in the presence of NVP, also showed approximately 50% less synthesis of Ach and vesicle numbers 43% lower than that seen in control muscles treated in the same way in the absence of drug. The results indicate a correlation between the inhibitory effect of NVP on ChAc and the numbers of vesicles present within terminals. In addition, stimulation of nerve terminals, with or without NVP, produced a significant increase in the numerical density of synaptic vesicles over respective unstimulated controls. These and other results are discussed in relation to current hypotheses concerning recirculation of synaptic vesicles.
本研究比较了在有或没有ChAc抑制剂NVP的情况下，高频和低频刺激青蛙胸肌神经肌肉接头处胆碱乙酰转移酶（ChAc）的活性与突触小泡的形态计量学测定结果。在NVP存在的情况下，以10次/秒的频率刺激肌肉20分钟，休息1小时，与对照制剂相比，乙酰胆碱（Ach）的合成减少了约50%，突触小泡的数量密度降低了50%-60%。在NVP存在的情况下，以2次/秒的频率刺激类似的神经肌肉制剂1小时，不休息，与在无药物情况下以相同方式处理的对照肌肉相比，Ach的合成也减少了约50%，小泡数量降低了43%。结果表明NVP对ChAc的抑制作用与终末内小泡数量之间存在相关性。此外，无论有无NVP，刺激神经终末都会使突触小泡的数量密度相对于各自未刺激的对照显著增加。这些结果以及其他结果将结合当前关于突触小泡再循环的假说进行讨论。
