REVIEW OF ELECTRON-MICROSCOPIC EVIDENCE FAVORING VESICLE EXOCYTOSIS AS THE STRUCTURAL BASIS FOR QUANTAL RELEASE DURING SYNAPTIC TRANSMISSION
REVIEW OF ELECTRON-MICROSCOPIC EVIDENCE FAVORING VESICLE EXOCYTOSIS AS THE STRUCTURAL BASIS FOR QUANTAL RELEASE DURING SYNAPTIC TRANSMISSION
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DOI：
10.1113/expphysiol.1989.sp003333
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发表时间：
1989-12-01
影响因子：
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通讯作者：
HEUSER, JE
中科院分区：
文献类型：
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作者：
HEUSER, JE
Katz和他的同事在他们对青蛙神经肌肉接头突触传递的早期电生理分析中概括了生物物理学的学科(Fatt&Katz，1950,1952；del Castillo&Katz，1954,1956)。使用当天最先进的微电极记录，他们记录了被钙剥夺或镁补充抑制的突触电位的长序列(图1，来自Fatt&Katz，1952)，然后对这些电位的幅度进行了仔细的数学分析(图2，来自del Castillo&Katz，1954)，以证明它们由一个或多个相对恒定的“单位”组成，这些单位具有与他们在早期记录的突触区域观察到的某些自发微型电去极化相同的幅度(图1)。这就引出了突触传递的“量子假说”：正常的诱发突触电位是由同时发生的微小而均匀的放电事件组成的，否则这些放电事件会在没有诱发的情况下以非常低的频率自发发生。这一假说在第一批成功的神经/肌肉突触电子显微照片中找到了肥沃的土壤(de Robertis，1958；Robertson，1956,1960a)。这些结果表明，在突触前的小膜泡中有一个恒定的存在，这立即表明，形成突触电位的量子或单一成分的相对统一的递质团可能包含在这些膜小泡中。这一所谓的“囊泡假说”是最初量子假说的扩展，如图3所示，出自del Castillo&Katz，1956年。这种对新技术的巧妙应用，敏锐的物理和数学分析，以及解释的才华，很可能是生物物理学最辉煌的时刻。事实上，这一学科本身在很大程度上是由这些早期活动定义的，因为它们发生在伦敦大学学院生物物理系的第一个系内，这个系是从伦敦大学学院已经创新的生理学系发展而来的。这个新部门的创始人A·V·希尔将其特殊的作用描述为提供住房和(培训)那些“那些天生具有身体直觉的人，那些能用身体语言表达问题的人，那些能在身体关系出现时识别出来的人，那些能用身体语言表达结果的人”。在引出这句话的精彩演讲中(希尔，1954)，希尔补充道：这些智力素质，比任何具有物理仪器和方法的特殊设施，对生物物理学家的构成都是必不可少的。B.卡茨就是这些特殊特征的例证，他在AV Hill之后继续担任生物物理系主任，培训了许多人，这些人后来成为世界各地该学科的知名人物。现在，随着生物物理学似乎正在融合
Katz and colleagues epitomized the discipline of biophysics in their early electrophysiological analysis of synaptic transmission at frog neuromuscular junctions (Fatt& Katz, 1950, 1952; del Castillo & Katz, 1954, 1956). Using microelectrode recording that was state of the art for that day, they recorded long series of synaptic potentials that had been suppressed by calcium deprivation or magnesium supplementation (Fig. 1, from Fatt & Katz, 1952), then performed careful mathematical analysis of the amplitudes of these potentials (Fig. 2, from del Castillo & Katz, 1954), to demonstrate that they were composed ofone or more relatively constant'units' that had the same amplitude as certain spontaneous miniature electrical depolarizations which they had observed in earlier recordings from synaptic areas (Fig. 1). This led them to the'quantal hypothesis' of synaptic transmission: the idea that normal evoked synapticpotentials are composed of the simultaneous occurrence of small and uniform discharge events that otherwise occur spontaneously at very low frequency in the absence of evocation. This hypothesis found fertile ground in the first successful electronic micrographs of nerve/muscle synapses (De Robertis, 1958; Robertson, 1956, 1960a). These revealed an invariable presence in the presynapse of small membranous vesicles, which immediately suggested that the relatively uniform boluses of transmitter forming the quantal or unitary components of the synaptic potential might be contained within such membranous vesicles. This so-called'vesicle hypothesis', an extension of the original quantal hypothesis, is diagrammed in Fig. 3, from del Castillo & Katz, 1956.This combination of skilful application of new techniques, astute physical and mathematical analysis, and interpretive brilliance may well have been biophysics' finest hour. Indeed, the discipline itself was largely defined by these early activities, since they happened within the first Biophysics Department, carved out of an already innovative Physiology Department at University College London. The founder of this new department, A. V. Hill, described its special role as housing and (training) those'to whom physical intuitions come naturally, who can state a problem in physical terms, who can recognize physical relations when they turn up, who can express results in physical terms'. In thefascinating lecture from which that quote was drawn (Hill, 1954), Hill added:'These intellectual qualities, more than any special facility with physical instruments and methods, are essential to the make-up of a biophysicist'. B. Katz exemplified these special characteristics, and carrying on as director of the Biophysics Department after AV Hill, trained many individuals who subsequently became notables in the discipline worldwide. Now, as biophysics appears to be merging