Sato K, Momose-Sato Y, Hirota A, Sakai T, Kamino K
Department of Physiology, Tokyo Medical and Dental University School of Medicine, Bunkyo-ku, Tokyo 113, Japan.
J Neurosci. 1998 Feb 15;18(4):1345-62. doi: 10.1523/JNEUROSCI.18-04-01345.1998.
We examined the functional organization of the vagal nuclei of the rat embryo during morphogenesis, using multiple-site optical recording with a voltage-sensitive dye. Slice preparations with vagus nerve fibers were dissected from 13- to 16-d-old embryonic (E13-E16) rat brainstems, and they were stained with the dye. Electrical activity in response to vagal stimulation was recorded optically from many sites. In the E13-E14 preparations, two types of spike-like optical signals were recorded: one was a narrow signal (type I), and the other was a broader signal (type II). Comparison with the morphology revealed by DiI labeling suggests that the type I signal response area corresponds to the nucleus of the tractus solitarius, and the type II signal response area corresponds to the dorsal motor nucleus of the vagus nerve. In the E15-E16 preparations, type I signals were followed by a slow signal related to glutamate-mediated excitatory postsynaptic potentials, suggesting that synaptic function is organized in the nucleus of the tractus solitarius by the 15-d-old embryonic stage. In the E14 preparation, a small, slow signal was evoked only in Mg2+-free solution, implying that postsynaptic function related to NMDA receptors emerges, in latent form, at the 14-d-old embryonic stage. In the E15 and E16 preparations, although the nucleus ambiguus is identified morphologically, no neural response-related optical signal was observed there, indicating that the embryonic organization of morphology and physiological function is not necessarily temporally coincident. We have mapped the dynamic spatiotemporal patterns of the evoked optical signals and have outlined the early phase of the functional organization of the cranial nuclei related to the vagus.
我们使用电压敏感染料进行多位点光学记录，研究了大鼠胚胎形态发生过程中迷走神经核的功能组织。从13至16日龄胚胎（E13 - E16）大鼠脑干中分离出带有迷走神经纤维的脑片标本，并用染料对其进行染色。从多个位点光学记录对迷走神经刺激的电活动。在E13 - E14的标本中，记录到两种类型的尖峰状光学信号：一种是窄信号（I型），另一种是较宽信号（II型）。与DiI标记显示的形态学比较表明，I型信号反应区域对应于孤束核，II型信号反应区域对应于迷走神经背运动核。在E15 - E16的标本中，I型信号之后跟着一个与谷氨酸介导的兴奋性突触后电位相关的慢信号，这表明在胚胎15日龄时孤束核中突触功能已组织化。在E14的标本中，仅在无镁溶液中诱发了一个小的慢信号，这意味着与NMDA受体相关的突触后功能在胚胎14日龄时以潜在形式出现。在E15和E16的标本中，尽管在形态学上已识别出疑核，但在那里未观察到与神经反应相关的光学信号，这表明形态学和生理功能的胚胎组织化不一定在时间上是一致的。我们绘制了诱发光学信号的动态时空模式，并勾勒出了与迷走神经相关的颅神经核功能组织的早期阶段。
