Hamann Martine, Billups Brian, Forsythe Ian D
Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester LE1 9HN, UK.
Eur J Neurosci. 2003 Nov;18(10):2899-902. doi: 10.1111/j.1460-9568.2003.03017.x.
Principal neurons of the medial nucleus of the trapezoid body (MNTB) receive a synaptic input from a single giant calyx terminal that generates a fast-rising, large excitatory postsynaptic current (EPSC), each of which are supra-threshold for postsynaptic action potential generation. Here, we present evidence that MNTB principal neurons receive multiple excitatory synaptic inputs generating slow-rising, small EPSCs that are also capable of triggering postsynaptic action potentials but are of non-calyceal origin. Both calyceal and non-calyceal EPSCs are mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and N-methyl-d-aspartate (NMDA) receptor activation; however, the NMDA receptor-mediated response is proportionally larger at the non-calyceal synapses. Non-calyceal synapses generate action potentials in MNTB principal neurons with a longer latency and a lower reliability than the large calyceal input. They constitute an alternative low fidelity synaptic input to the fast and secure relay transmission via the calyx of Held synapse.
梯形体内侧核（MNTB）的主要神经元从单个巨大花萼终末接收突触输入，该终末产生快速上升的大兴奋性突触后电流（EPSC），每个EPSC对于突触后动作电位的产生都是阈上的。在这里，我们提供证据表明，MNTB主要神经元接收多个兴奋性突触输入，产生缓慢上升的小EPSC，这些EPSC也能够触发突触后动作电位，但它们起源于非花萼。花萼和非花萼EPSC均由α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）和N-甲基-D-天冬氨酸（NMDA）受体激活介导；然而，NMDA受体介导的反应在非花萼突触处比例更大。非花萼突触在MNTB主要神经元中产生动作电位的潜伏期比大花萼输入更长，可靠性更低。它们构成了一种替代的低保真度突触输入，用于通过Held花萼突触进行快速且安全的中继传递。
