Analysis of development and remodeling of neural circuit related to the visceral reflexes in the medulla and spinal cord

(1)小鼠内脏反射相关神经通路的成体学研究：为了阐明哺乳动物内脏反射相关神经通路的产生过程，我们对产前小鼠感觉神经中TRPV1的表达进行了研究。在E13的背根神经节细胞中观察到TRPV1，在脊髓的中央终末也观察到TRPV1。TRPV1在不同脏器外周过程中的表达周期不同，即在E14-15时在尿路和直肠，在E18-P1时在气管和支气管。此外，各器官间TRPV1与降钙素基因相关肽（CGRP）共存率差异较大；因此，支气管和尿道的共存率较高，而胃和大肠的共存率较低。此外，在产前小鼠脊髓中，TRPV1阳性纤维和CGRP阳性纤维通过E16直接投射到骶水平的副交感神经节前细胞。因此，与泌尿道和下消化道内脏反射相关的反射回路可能是由E16完成的。2)与内脏反射有关的神经回路的系统发育研究：通过对蝮蛇面神经的示踪实验，证实了具有一般内脏传出性质的唾上核的存在和位置。该核介导上下颌唾液腺分泌，也参与坑膜的血流调节，坑膜是蝮蛇的红外受体。由于唾液腺上核靠近热量核，热量核是红外感觉的传递核，推测红外感觉可能通过热量核影响颅副交感神经系统。我们还探讨了起源于非洲爪蟾背根神经节的感觉神经终止于腹腔神经节的可能性。在病变实验和辣椒素药物实验中，包围神经节细胞的大部分神经纤维消失。此外，将示踪剂注入腹腔神经节后，背根神经节内的许多神经元被逆行标记，其中含有SP。由此提示，两栖动物中感觉神经也通过轴突侧枝对交感神经节后细胞进行反射性调节的可能性较小

(1) Ontogenic study of the neural pathways related to mouse visceral reflexes: In order to clarify the generating process of neural pathways related to the visceral reflexes of mammals, expression of TRPV1 in sensory nerves was investigated in prenatal mice. TRPV1 was observed in the dorsal root ganglion cells at E13, and also in the central terminals in the spinal cord. The period of TRPV1 expression in the peripheral processes was different among viscera, i.e., in the urinary tract and the rectum at E14-15, and in the trachea and in the bronchi at E18-P1. Moreover, the rate of coexistence of TRPV1 and calcitonin gene-related peptide (CGRP) varied greatly among organs; thus, the bronchi and the urinary tract showed a high rate of coexistence, and in the stomach and the large intestine, the rate was low. Moreover, in the spinal cord of prenatal mice, TRPV1 positive fibers and CGRP positive fibers projected directly to the parasympathetic preganglionic cells at the sacral level by E16. … More Therefore, the possibility that the reflective circuit related to the visceral reflexes from the urinary tract and the lower alimentary canal is completed by E16 was shown.2) Phylogenic study of the neural circuit related to the visceral reflex: In the tracer experiments on the facial nerve of a pit viper, the existence and location of the superior salivary nucleus, which is general visceral efferent in nature, were confirmed. This nucleus mediates salivary gland secretion of the upper and lower jaws, and also participates in blood-flow regulation in the pit membrane, an infrared receptor of pit vipers. Since the superior salivary nucleus was close to the nucleus caloris which is a relay nucleus of infrared sensation, it was surmised that infrared sensation may affect the cranial parasympathetic nervous system through the nucleus caloris. We also explored the possibility that the sensory nerves originating in the dorsal root ganglia terminate in the celiac ganglion of Xenopus. When lesion experiments and capsaicin medication experiments were conducted, most nerve fibers enclosing the ganglion cells disappeared. Moreover, when the tracer was injected into the celiac ganglion, many neurons in the dorsal root ganglia were retrogradely labeled, and they contained SP. From this, the possibility that the sensory nerves perform reflective regulation via axon collaterals to the sympathetic postganglionic cells also in amphibians was suggested Less