Wiley R G, Spencer C, Pysh J J
J Neurocytol. 1987 Jun;16(3):359-72. doi: 10.1007/BF01611347.
The mammalian superior cervical sympathetic ganglion has been extensively used to study the kinetics of ACh metabolism and release. The present investigation examined the time course of changes in the number of synaptic vesicles and abundance of plasma membrane at preganglionic nerve terminals using stimulation protocols similar to those used in previous biochemical and electrophysiological studies. Continuous stimulation of the preganglionic trunk to the cat superior cervical ganglion in vivo produced an initially rapid fall in the number of clear synaptic vesicles followed by a subsequent plateau. Reciprocal changes in plasma membrane occurred with a similar time course. The plateau phase is interpreted as a steady-state where vesicle exocytosis is balanced by the rate of vesicle reformation from plasma membrane. During quiescent recovery, restoration of normal resting ultrastructure is initially rapid but slows with time as vesicle number and plasma membrane abundance approach pre-stimulation values, indicating that the rate of vesicle reformation at the end of stimulation is high and proportional to the number of vesicles incorporated into the plasma membrane. These results are interpreted as consistent with the 'vesicle hypothesis' of neurotransmitter release.
哺乳动物的颈上神经节已被广泛用于研究乙酰胆碱代谢和释放的动力学。本研究使用与先前生化和电生理研究中相似的刺激方案，检测了节前神经末梢突触小泡数量和质膜丰度的时间变化过程。在体内持续刺激猫颈上神经节的节前干，最初会使清亮突触小泡数量迅速下降，随后趋于平稳。质膜发生了相反的变化，且时间进程相似。平稳期被解释为一种稳态，即小泡胞吐作用与质膜形成小泡的速率达到平衡。在静止恢复期间，正常静息超微结构的恢复最初很快，但随着时间推移会减慢，因为小泡数量和质膜丰度接近刺激前的值，这表明刺激结束时小泡形成的速率很高，且与并入质膜的小泡数量成正比。这些结果被解释为与神经递质释放的“小泡假说”一致。
