Release of acetylcholine from embryonic neurons upon contact with muscle cell
Release of acetylcholine from embryonic neurons upon contact with muscle cell
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与肌肉细胞接触后胚胎神经元释放乙酰胆碱
DOI：
10.1523/jneurosci.05-04-01076.1985
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
M. Poo
中科院分区：
文献类型：
--
作者：
I. Chow;M. Poo
当一个球形的肌肉细胞（myoball）被操纵到接触的索马或一个孤立的神经元的轴突在2天大的非洲爪蟾神经肌肉文化，去极化类似于微型终板电位（MEPPs）经常检测到的肌肉细胞。这些去极化发生在肌球-胞体接触后数分钟内和肌球-神经突接触后数秒内。他们的时间过程和振幅分布类似的MEPP记录从自然发生的神经肌肉突触之间的神经突起和肌肉细胞在相同的文化，但他们发生在一个较低的频率和较小的平均振幅。这些去极化由乙酰胆碱（ACh）诱导，因为它们被可逆地阻断加入d-筒箭毒碱到培养物中，并且它们在与神经元接触之前在用α-银环蛇毒素预处理的肌细胞中被废除。这些培养物中超过60%的神经元群体在这种直接肌肉接触时释放ACh。在与分离的神经元接触时，肌球中出现MEPP样电位，表明负责ACh释放的细胞机制存在于整个神经元中，并且ACh分子包可在神经-肌肉突触形成之前释放。我们还发现，以前与其他肌细胞形成突触的神经元在与肌球接触的前30分钟至1小时内，都不能从索马体释放ACh，并且在轴突处显示出降低的释放能力。这一发现表明，在突触发生过程中，有一个耗尽的乙酰胆碱分子和/或物质负责触发其释放的突触外区域的神经元。
When a spherical muscle cell (myoball) was manipulated into contact with either the soma or the neurite of an isolated neuron in 2-day-old Xenopus nerve-muscle cultures, depolarizations similar to miniature endplate potentials (MEPPs) were frequently detected in the muscle cell. These depolarizations occurred within minutes after myoball-soma contact and within seconds after myoball-neurite contact. They had time course and amplitude distribution similar to those of the MEPPs recorded from naturally occurring neuromuscular synapses between neurites and muscle cells found in the same cultures, but they occurred at a lower frequency and had smaller average amplitudes. These depolarizations were induced by acetylcholine (ACh) since they were reversibly blocked by addition of d-tubocurarine into the culture, and they were abolished in muscle cells pretreated with alpha-bungarotoxin before contact with the neuron. Greater than 60% of the neuronal population in these cultures released ACh upon this direct muscle contact. The appearance of MEPP-like potentials in the myoball upon contact with an isolated neuron suggests that the cellular machinery responsible for ACh release is present throughout the neuron and that packages of ACh molecules are available for release prior to nerve- muscle synapse formation. We also found that neurons which had previously made synapse with other muscle cells in the culture all failed to release ACh from the soma and showed reduced release capability at the neurite for the first 30 min to 1 hr of contact with a myoball. This finding suggests that, during synapatogenesis, there is a depletion of ACh molecules and/or substances responsible for the triggering of their release in the extrasynaptic regions of the neuron.