Wall M J, Usowicz M M
Department of Pharmacology, University of Bristol, UK.
Nat Neurosci. 1998 Dec;1(8):675-82. doi: 10.1038/3677.
In many studies of central synaptic transmission, the quantal properties of miniature synaptic events do not match those derived from synaptic events evoked by action potentials. Here we show that at mossy fiber-granule cell (MF-gc) synapses of mature cerebellum, evoked excitatory postsynaptic currents (EPSCs) are multiquantal, and their amplitudes vary in discrete steps, whereas miniature (m)EPSCs are monoquantal or multiquantal with quantal parameters identical to those of the EPSCs. In contrast, at immature MF-gc synapses, EPSCs are multiquantal, but their amplitudes do not vary in discrete steps, whereas most mEPSCs seem to be monoquantal with a broad and skewed amplitude distribution. The results demonstrate that quantal variance decreases during synaptic development. They also directly confirm the quantal hypothesis of neurotransmission at a mature brain synapse.
在许多中枢突触传递的研究中，微小突触事件的量子特性与动作电位诱发的突触事件所推导的特性不匹配。在此我们表明，在成熟小脑的苔藓纤维-颗粒细胞（MF-gc）突触处，诱发的兴奋性突触后电流（EPSC）是多量子的，其幅度以离散步骤变化，而微小（m）EPSC是单量子或多量子的，其量子参数与EPSC相同。相比之下，在未成熟的MF-gc突触处，EPSC是多量子的，但其幅度不以离散步骤变化，而大多数mEPSC似乎是单量子的，具有广泛且偏态的幅度分布。结果表明，在突触发育过程中量子变异性降低。它们还直接证实了成熟脑突触处神经传递的量子假说。
