Matsui Ko, Jahr Craig E
Division of Cerebral Structure, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8787, Japan.
Curr Opin Neurobiol. 2006 Jun;16(3):305-11. doi: 10.1016/j.conb.2006.04.001. Epub 2006 May 3.
The accepted theory of vesicular release of neurotransmitter posits that only a single vesicle per synapse can fuse with the membrane following action potential invasion, and this exocytotic event is limited to the ultrastructurally defined presynaptic active zone. Neither of these dictums is universally true. At certain synapses, more than a single vesicle can be released per action potential, and there is growing evidence that neuronal exocytosis can occur from sites that are unremarkable in electron micrographs. The first discrepancy extends the dynamic range of synapses, whereas the second enables faster and more robust chemical transmission at sites distant from morphologically defined synapses. Taken together, these attributes expand the capabilities of cellular communication in the nervous system.
关于神经递质囊泡释放的公认理论认为，在动作电位侵入后，每个突触仅有一个囊泡能与膜融合，且这种胞吐事件局限于超微结构定义的突触前活性区。这两条准则并非普遍适用。在某些突触，每个动作电位可释放不止一个囊泡，并且越来越多的证据表明，神经元胞吐作用可发生于电子显微镜图像中并无明显特征的部位。第一个差异扩展了突触的动态范围，而第二个差异使远离形态学定义突触的部位能够实现更快、更强健的化学传递。综上所述，这些特性扩展了神经系统中细胞通讯的能力。
