In vertebrate motor nerve terminals and in the electromotor nerve terminals of Torpedo there are two major pools of synaptic vesicles: readily releasable and reserve. The electromotor terminals differ in that the reserve vesicles are twice the diameter of the readily releasable vesicles. The vesicles contain high concentrations of ACh and ATP. Part of the ACh is brought into the vesicle by the vesicular ACh transporter, VAChT, which exchanges two protons for each ACh, but a fraction of the ACh seems to be accumulated by different, unexplored mechanisms. Most of the vesicles in the terminals do not exchange ACh or ATP with the axoplasm, although ACh and ATP are free in the vesicle interior. The VAChT is controlled by a multifaceted regulatory complex, which includes the proteoglycans that characterize the cholinergic vesicles. The drug (-)-vesamicol binds to a site on the complex and blocks ACh exchange. Only 10-20% of the vesicles are in the readily releasable pool, which therefore is turned over fairly rapidly by spontaneous quantal release. The turnover can be followed by the incorporation of false transmitters into the recycling vesicles, and by the rate of uptake of FM dyes, which have some selectivity for the two recycling pathways. The amount of ACh loaded into recycling vesicles in the readily releasable pool decreases during stimulation. The ACh content of the vesicles can be varied over eight-fold range without changing vesicle size.

中文翻译：

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鱼雷电器官和脊椎动物神经肌肉接头中突触小泡的装载和回收。

在脊椎动物的运动神经末梢和鱼雷的运动神经末梢中，有两个主要的突触囊泡池：易于释放和储备。电动机端子的不同之处在于，储备囊泡的直径是易于释放囊泡的直径的两倍。囊泡中含有高浓度的ACh和ATP。ACh的一部分由囊泡ACh转运蛋白VAChT带入囊泡，VAChT为每个ACh交换两个质子，但是一部分ACh似乎是由不同的，尚未探索的机制积累的。尽管ACh和ATP在囊泡内部是自由的，但末端的大多数囊泡都不与轴质交换ACh或ATP。VAChT由多方面的调控复合物控制，其中包括表征胆碱能小泡的蛋白聚糖。药物（-）-vesamicol与复合物上的位点结合并阻断ACh交换。只有10-20％的囊泡处于易于释放的池中，因此通过自发的定量释放可以相当快地将其翻转。周转可以通过将错误的递质掺入回收囊泡中，以及通过FM染料的吸收速率来实现，而FM染料对两种回收途径具有一定的选择性。在刺激过程中，容易释放的池中装入回收囊泡的ACh量减少。囊泡的ACh含量可以在八倍范围内变化，而不会改变囊泡的大小。周转可以通过将错误的递质掺入回收囊泡中，以及通过FM染料的吸收速率来实现，而FM染料对两种回收途径具有一定的选择性。在刺激过程中，容易释放的池中装入回收囊泡的ACh量减少。囊泡的ACh含量可以在八倍范围内变化，而不会改变囊泡的大小。周转可以通过将错误的递质掺入回收囊泡中，以及通过FM染料的吸收速率来实现，而FM染料对两种回收途径具有一定的选择性。在刺激过程中，容易释放的池中装入循环囊泡中的ACh量减少。囊泡的ACh含量可以在八倍范围内变化，而不会改变囊泡的大小。