Luan Xiao, Sun Xiangrong, Guo Feifei, Zhang Di, Wang Cheng, Ma Li, Xu Luo
Department of Pathophysiology, Medical College of Qingdao University, Qingdao, China.
Departmemt of Clinical Nutrition, Affiliated Hospital, Qingdao University, Qingdao, China.
J Neurochem. 2017 Dec;143(6):697-707. doi: 10.1111/jnc.14233. Epub 2017 Nov 7.
It has been well-known that hypothalamic orexigenic neuropeptides, orexin-A, and melanin-concentrating hormone (MCH), play important roles in regulation of gastric function. However, what neural pathway mediated by the two neuropeptides affects the gastric function remains unknown. In this study, by way of nucleic stimulation and extracellular recording of single unit electrophysiological properties, we found that electrically stimulating the lateral hypothalamic area (LH) or microinjection of orexin-A into the arcuate nucleus (ARC) excited most gastric distension-responsive neurons in the nuclei and enhanced the gastric function including motility, emptying, and acid secretion of conscious rats. The results indicated that LH-ARC orexin-A-ergic projections may exist and the orexin-A in the ARC affected afferent and efferent signal transmission between ARC and stomach. As expected, combination of retrograde tracing and immunohistochemistry showed that some orexin-A-ergic neurons projected from the LH to the ARC. In addition, microinjection of MCH and its receptor antagonist PMC-3881-PI into the ARC affected the role of orexin-A in the ARC, indicating a possible involvement of the MCH pathway in the orexin-A role. Our findings suggest that there was an orexin-A-ergic pathway between LH and ARC which participated in transmitting information between the central nuclei and the gastrointestinal tract and in regulating the gastric function of rats.
众所周知，下丘脑促食欲神经肽、食欲素-A和促黑素细胞激素（MCH）在胃功能调节中发挥重要作用。然而，这两种神经肽介导的何种神经通路影响胃功能仍不清楚。在本研究中，通过对单个单位电生理特性进行核刺激和细胞外记录，我们发现电刺激下丘脑外侧区（LH）或向弓状核（ARC）微量注射食欲素-A可兴奋该核团中大多数对胃扩张有反应的神经元，并增强清醒大鼠的胃功能，包括胃动力、排空和胃酸分泌。结果表明，可能存在LH-ARC食欲素-A能投射，ARC中的食欲素-A影响ARC与胃之间的传入和传出信号传递。正如预期的那样，逆行追踪和免疫组织化学相结合显示，一些食欲素-A能神经元从LH投射到ARC。此外，向ARC微量注射MCH及其受体拮抗剂PMC-3881-PI会影响食欲素-A在ARC中的作用，表明MCH通路可能参与了食欲素-A的作用。我们的研究结果表明，LH和ARC之间存在一条食欲素-A能通路，该通路参与中枢核团与胃肠道之间的信息传递，并调节大鼠的胃功能。
