Edwards Robert H
Department of Neurology and Physiology, UCSF School of Medicine, San Francisco, CA 94158-2517, USA.
Neuron. 2007 Sep 20;55(6):835-58. doi: 10.1016/j.neuron.2007.09.001.
Changes in the response to release of a single synaptic vesicle have generally been attributed to postsynaptic modification of receptor sensitivity, but considerable evidence now demonstrates that alterations in vesicle filling also contribute to changes in quantal size. Receptors are not saturated at many synapses, and changes in the amount of transmitter per vesicle contribute to the physiological regulation of release. On the other hand, the presynaptic factors that determine quantal size remain poorly understood. Aside from regulation of the fusion pore, these mechanisms fall into two general categories: those that affect the accumulation of transmitter inside a vesicle and those that affect vesicle size. This review will summarize current understanding of the neurotransmitter cycle and indicate basic, unanswered questions about the presynaptic regulation of quantal size.
对单个突触小泡释放的反应变化通常归因于受体敏感性的突触后修饰，但现在有大量证据表明，小泡填充的改变也会导致量子大小的变化。在许多突触中，受体并未饱和，每个小泡中神经递质数量的变化有助于释放的生理调节。另一方面，决定量子大小的突触前因素仍知之甚少。除了融合孔的调节外，这些机制大致可分为两类：影响神经递质在小泡内积累的机制和影响小泡大小的机制。本综述将总结目前对神经递质循环的理解，并指出关于量子大小突触前调节的基本未解决问题。
