Momose-Sato Yoko, Sato Katsushige
Department of Physiology, Tokyo Medical and Dental University, Graduate School and Faculty of Medicine, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
Auton Neurosci. 2006 Jun 30;126-127:39-49. doi: 10.1016/j.autneu.2006.02.013. Epub 2006 Apr 17.
Multiple-site optical recording with a fast voltage-sensitive dye, absorption dye NK2761, was used to study the developmental organization of functional synaptic networks in the vagal pathway. Glutamatergic excitatory postsynaptic potentials (EPSPs) evoked by vagus nerve stimulation was first detected from the nucleus of the tractus solitarius (NTS) at embryonic day 7 (E7) in chick embryos and E15 in rat embryos, when morphological differentiation of pre- and postsynaptic neurons is incomplete. When extracellular Mg2+ was removed, small EPSPs were elicited at E6 in chick embryos and E14 in rat embryos. These results suggest that synaptic function mediated by N-methyl-D-aspartate (NMDA) receptors is latently generated 1 day before the expression of glutamatergic EPSP. Functional synapses related to the glossophyaryngeal nerve appear to be generated at the same time as the vagus nerve, but their spatial distribution was different from that of the vagus nerve. We further investigated the development of second synaptic pathways from the NTS to higher centers, and found that neuronal circuits from the NTS are already generated when the primary afferents form functional synapses with NTS neurons.
使用快速电压敏感染料吸收染料NK2761进行多部位光学记录，以研究迷走神经通路中功能性突触网络的发育组织。在鸡胚胚胎第7天（E7）和大鼠胚胎E15时，首次从孤束核（NTS）检测到迷走神经刺激诱发的谷氨酸能兴奋性突触后电位（EPSP），此时突触前和突触后神经元的形态分化尚未完成。当去除细胞外Mg2+时，在鸡胚E6和大鼠胚胎E14时诱发了小的EPSP。这些结果表明，由N-甲基-D-天冬氨酸（NMDA）受体介导的突触功能在谷氨酸能EPSP表达前1天就已潜在产生。与舌咽神经相关的功能性突触似乎与迷走神经同时产生，但其空间分布与迷走神经不同。我们进一步研究了从NTS到高级中枢的第二突触通路的发育，发现当初级传入神经与NTS神经元形成功能性突触时，来自NTS的神经回路已经形成。
