Guan Jian-Lian, Wang Qing-Ping, Kageyama Haruaki, Kita Tetsuro, Takenoya Fumiko, Hori Tomoko, Shioda Seiji
Department of Anatomy, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
Regul Pept. 2005 Jul 15;129(1-3):17-23. doi: 10.1016/j.regpep.2005.01.008.
The distribution of orexin A immunoreactivity and the synaptic relationships of orexin A-positive neurons in the rat area postrema were studied using both light and electron microscopy techniques. At the light microscope level, numerous orexin A-like immunoreactive fibers were found within the area postrema. Using electron microscopy, immunoreactivity within fibers was confined primarily to the axon terminals, most of which contained dense-cored vesicles. Both axo-somatic and axo-dendritic synapses made by orexin A-like immunoreactive axon terminals were found, with these synapses being both symmetric and asymmetric in form. Orexin A-like immunoreactive axon terminals could be found presynaptic to two different immunonegative profiles including the perikarya and dendrites. Occasionally, some orexin A-like immunoreactive profiles, most likely to be dendrites, could be seen receiving synaptic inputs from immunonegative or immunopositive axon terminals. The present results suggest that the physiological function of orexin A in the area postrema depends on synaptic relationships with other immunopositive and immunonegative neurons, with the action of orexin A mediated via a self-modulation feedback mechanism.
运用光学显微镜和电子显微镜技术，研究了大鼠最后区中食欲素A免疫反应性的分布以及食欲素A阳性神经元的突触关系。在光学显微镜水平上，最后区内发现了大量食欲素A样免疫反应纤维。利用电子显微镜观察到，纤维内的免疫反应性主要局限于轴突终末，其中大多数含有致密核心小泡。发现了由食欲素A样免疫反应性轴突终末形成的轴-体和轴-树突触，这些突触在形态上既有对称的也有不对称的。食欲素A样免疫反应性轴突终末可位于两种不同的免疫阴性结构（包括胞体和树突）的突触前。偶尔，可以看到一些最有可能是树突的食欲素A样免疫反应性结构接受来自免疫阴性或免疫阳性轴突终末的突触输入。目前的结果表明，最后区中食欲素A的生理功能取决于与其他免疫阳性和免疫阴性神经元的突触关系，食欲素A的作用是通过一种自我调节反馈机制介导的。
