Morinaga Ryosuke, Nakamuta Nobuaki, Yamamoto Yoshio
Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-Chome, Morioka, Iwate 020-8550, Japan; Department of Basic Veterinary Science, United Graduate School of Veterinary Science, Gifu University, 1-1, Yanagido, Gifu 501-1193, Japan.
Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-Chome, Morioka, Iwate 020-8550, Japan; Department of Basic Veterinary Science, United Graduate School of Veterinary Science, Gifu University, 1-1, Yanagido, Gifu 501-1193, Japan.
Neurosci Res. 2019 Jun;143:20-30. doi: 10.1016/j.neures.2018.05.004. Epub 2018 May 24.
The ventral respiratory column (VRC) generates rhythmical respiration and is divided into four compartments: the Bötzinger complex (BC), pre-Bötzinger complex (PBC), rostral ventral respiratory group (rVRG), and caudal ventral respiratory group (cVRG). Serotonergic nerve fibers are densely distributed in the rostral to caudal VRC and serotonin would be one of the important modulators for the respiratory control in the VRC. In the present study, to elucidate detailed distribution of serotonergic neurons in raphe nuclei projecting to the various rostrocaudal levels of VRC, we performed combination of retrograde tracing technique by cholera toxin B subunit (CTB) with immunohistochemistry for tryptophan hydroxylase 2 (TPH2). The double-immunoreactive neurons with CTB and TPH2 were distributed in the both rostral and caudal raphe nuclei, i.e. dorsal raphe nucleus, raphe magnus nucleus, gigantocellular reticular nucleus alpha and ventral parts, lateral paragigantocellular nucleus, parapyramidal area, raphe obscurus nucleus, and raphe pallidus nucleus. The distributions of double-immunoreactive neurons were similar among injection groups of BC, PBC, anterior rVRG, and posterior rVRG/cVRG. In conclusion, serotonergic neurons in both rostral and caudal raphe nuclei projected throughout the VRC and these serotonergic projections may contribute to respiratory responses to various environmental and vital changes.
腹侧呼吸柱（VRC）产生节律性呼吸，分为四个部分：包钦格复合体（BC）、前包钦格复合体（PBC）、吻侧腹侧呼吸组（rVRG）和尾侧腹侧呼吸组（cVRG）。5-羟色胺能神经纤维密集分布于VRC的吻侧至尾侧，5-羟色胺可能是VRC呼吸控制的重要调节因子之一。在本研究中，为了阐明中缝核中投射至VRC不同吻尾水平的5-羟色胺能神经元的详细分布，我们将霍乱毒素B亚基（CTB）逆行示踪技术与色氨酸羟化酶2（TPH2）免疫组织化学相结合。CTB和TPH2双免疫反应性神经元分布于吻侧和尾侧中缝核，即背侧中缝核、中缝大核、巨细胞网状核α及腹侧部、外侧旁巨细胞网状核、锥体旁区、中缝隐核和中缝苍白核。BC、PBC、吻侧rVRG前部及rVRG后部/cVRG注射组中双免疫反应性神经元的分布相似。总之，吻侧和尾侧中缝核中的5-羟色胺能神经元投射至整个VRC，这些5-羟色胺能投射可能有助于机体对各种环境和生命变化产生呼吸反应。
