Momose-Sato Yoko, Sato Katsushige
Department of Nutrition and Dietetics, College of Nutrition, Kanto Gakuin University, Kanazawa-ku, Yokohama 236-8503, Japan.
Department of Health and Nutrition Sciences, Komazawa Women's University Faculty of Human Health, Inagi-shi, Tokyo 206-8511, Japan.
IBRO Rep. 2019 May 14;6:176-184. doi: 10.1016/j.ibror.2019.05.004. eCollection 2019 Jun.
The glossopharyngeal nerve (N.IX) transfers motor and sensory information related to visceral and somatic functions, such as salivary secretion, gustation and the control of blood pressure. N.IX-related neural circuits are indispensable for these essential functions. Compared with the strenuous analysis of morphogenesis, we are only just starting to elucidate the functiogenesis of these neural circuits during ontogenesis. In the present study, we applied voltage-sensitive dye recording to the embryonic mouse brainstem, and examined the functional development of the N.IX-related neural circuits. First, we optically identified the motor nucleus (the inferior salivatory nucleus (ISN)) and the first-order sensory nucleus (the nucleus of the tractus solitarius (NTS)). We also succeeded in recording optical responses in the second/higher-order sensory nuclei via the NTS, including the parabrachial nucleus. Second, we pursued neuronal excitability and the onset of synaptic function in the N.IX-related nuclei. The neurons in the ISN were excitable at least at E11, and functional synaptic transmission in the NTS was first expressed at E12. In the second/higher-order sensory nuclei, synaptic function emerged at around E12-13. Third, by mapping optical responses to N.IX and vagus nerve (N.X) stimulation, we showed that the distribution patterns of neural activity in the NTS were different between the N.IX and the N.X from the early stage of ontogenesis. We discuss N.IX-related neural circuit formation in the brainstem, in comparison with our previous results obtained from chick and rat embryos.
舌咽神经（第九对脑神经）传递与内脏和躯体功能相关的运动和感觉信息，如唾液分泌、味觉和血压控制。与形态发生的深入分析相比，我们才刚刚开始阐明这些神经回路在个体发育过程中的功能发生。在本研究中，我们将电压敏感染料记录应用于胚胎小鼠脑干，研究了与第九对脑神经相关的神经回路的功能发育。首先，我们通过光学方法确定了运动核（下涎核（ISN））和一级感觉核（孤束核（NTS））。我们还成功地通过NTS记录了包括臂旁核在内的二级/高级感觉核中的光学反应。其次，我们研究了与第九对脑神经相关核团中的神经元兴奋性和突触功能的起始。ISN中的神经元至少在胚胎第11天就具有兴奋性，NTS中的功能性突触传递在胚胎第12天首次表达。在二级/高级感觉核中，突触功能在胚胎第12 - 13天左右出现。第三，通过绘制对第九对脑神经和迷走神经（第十对脑神经）刺激的光学反应图，我们发现从个体发育早期开始，NTS中神经活动的分布模式在第九对脑神经和第十对脑神经之间就有所不同。我们将与之前从鸡和大鼠胚胎获得的结果进行比较，讨论脑干中与第九对脑神经相关的神经回路形成。
