Pan Xu-Chu, Song Yong-Tang, Liu Cheng, Xiang Hong-Bing, Lu Chuan-Jian
Medical Association of Hubei Province, Wuhan, 430060, China.
Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
J Huazhong Univ Sci Technolog Med Sci. 2013 Apr;33(2):195-198. doi: 10.1007/s11596-013-1096-9. Epub 2013 Apr 17.
The rostral ventromedial medulla (RVM) is a prominent component of the descending modulatory system involved in the control of spinal nociceptive transmission. In the current study, we investigated melanocortin-4 receptor (MC4R) expression in the RVM, where the neurons involved in modulation of nociception reside. Using a line of mice expressing green fluorescent protein (GFP) under the control of the MC4R promoter, we found a large number of GFP-positive neurons in the RVM [nucleus raphe magnus (NRM) and nucleus gigantocellularis pars α (NGCα)]. Fluorescence immunohistochemistry revealed that approximately 10% of MC4R-GFP-positive neurons coexpressed tyrosine hydroxylase, indicating that they were catecholaminergic, whereas 50%-75% of those coexpressed tryptophan hydroxylase, indicating that they were serotonergic. Our findings support the hypothesis that MC4R signaling in RVM may modulate the activity of serotonergic sympathetic outflow sensitive to nociceptive signals, and that MC4R signaling in RVM may contribute to the descending modulation of nociceptive transmission.
延髓头端腹内侧区（RVM）是下行调制系统的一个重要组成部分，参与脊髓伤害性感受传递的控制。在本研究中，我们调查了RVM中促黑素细胞激素4受体（MC4R）的表达情况，RVM是参与伤害性感受调制的神经元所在之处。利用在MC4R启动子控制下表达绿色荧光蛋白（GFP）的小鼠品系，我们在RVM [中缝大核（NRM）和巨细胞网状核α部（NGCα）]中发现了大量GFP阳性神经元。荧光免疫组织化学显示，约10%的MC4R-GFP阳性神经元共表达酪氨酸羟化酶，表明它们是儿茶酚胺能的，而50%-75%的此类神经元共表达色氨酸羟化酶，表明它们是5-羟色胺能的。我们的研究结果支持以下假设：RVM中的MC4R信号传导可能调节对伤害性信号敏感的5-羟色胺能交感神经传出活动，并且RVM中的MC4R信号传导可能有助于伤害性感受传递的下行调制。
