Ciriello John, Caverson Monica M
Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada N6A 5C1.
Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada N6A 5C1.
Brain Res. 2014 Sep 4;1579:20-34. doi: 10.1016/j.brainres.2014.07.008. Epub 2014 Jul 10.
Immunohistochemistry combined with retrograde tract-tracing techniques were used to investigate the distribution of orexin-A (OX-A)- and OX-A receptor-like (OX1) immunoreactivity within the vestibular complex and cerebellum, and the location of hypothalamic OX-A neurons sending axonal projections to these regions in the Wistar rat. OX-A immunoreactive fibers and presumptive terminals were found throughout the medial (MVe) and lateral (LVe) vestibular nuclei. Light fiber labeling was also observed in the spinal and superior vestibular nuclei. Within the cerebellum, dense fiber and presumptive terminal labeling was observed in the medial cerebellar nucleus (Med; fastigial nucleus), with less dense labeling in the interposed (Int) and lateral cerebellar nuclei (Lat; dentate nucleus). A few scattered OX-A immunoreactive fibers were also observed throughout the cortex of the paraflocculus. OX1-like immunoreactivity was found densely concentrated within LVe, moderate in MVe, and scattered within the spinal and superior vestibular nuclei. Within the cerebellum, OX1-like immunoreactivity was also observed densely within Med and in the dorsolateral aspects of Int. Additionally, OX1 like-labeling was found in Lat, and within the granular layer of the caudal paraflocculus cerebellar cortex. Fluorogold (FG) microinjected into these vestibular and cerebellar regions resulted in retrogradely labeled neurons throughout the ipsilateral hypothalamus. Retrogradely labeled neurons containing OX-A like immunoreactivity were observed dorsal and caudal to the anterior hypothalamic nucleus and extending laterally into the lateral hypothalamic area, with the largest number clustered around the dorsal aspects of the fornix in the perifornical area. A few FG OX-A like-immunoreactive neurons were also observed scattered throughout the dorsomedial, and posterior hypothalamic nuclei. These data indicate that axons from OX-A neurons terminate within the vestibular complex and deep cerebellar nuclei of the cerebellum and although the function of these pathways is unknown, they likely represent pathways by which hypothalamic OX-A containing neurons co-ordinate vestibulo-cerebellar motor and autonomic functions associated with ingestive behaviors.
采用免疫组织化学结合逆行示踪技术，研究了Wistar大鼠前庭复合体和小脑中食欲素A（OX-A）及OX-A受体样（OX1）免疫反应性的分布，以及向这些区域发出轴突投射的下丘脑OX-A神经元的位置。在整个内侧（MVe）和外侧（LVe）前庭核中均发现了OX-A免疫反应性纤维和推测的终末。在脊髓和上前庭核中也观察到轻度的纤维标记。在小脑中，在内侧小脑核（Med；顶核）中观察到密集的纤维和推测的终末标记，在间位核（Int）和外侧小脑核（Lat；齿状核）中的标记较稀疏。在旁绒球皮质中也观察到一些散在的OX-A免疫反应性纤维。OX1样免疫反应性在LVe中密集分布，在MVe中中等分布，在脊髓和上前庭核中散在分布。在小脑中，OX1样免疫反应性在Med和Int的背外侧也密集观察到。此外，在Lat以及尾侧旁绒球小脑皮质的颗粒层中也发现了OX1样标记。向这些前庭和小脑区域微量注射荧光金（FG），导致同侧下丘脑出现逆行标记的神经元。观察到含有OX-A样免疫反应性的逆行标记神经元位于下丘脑前核的背侧和尾侧，并向外侧延伸至外侧下丘脑区，最大数量的神经元聚集在穹窿背侧周围的穹窿周区。在背内侧和下丘脑后核中也观察到一些散在的FG OX-A样免疫反应性神经元。这些数据表明，来自OX-A神经元的轴突终止于前庭复合体和小脑的深部小脑核，尽管这些通路的功能尚不清楚，但它们可能代表了含有下丘脑OX-A的神经元协调与摄食行为相关的前庭-小脑运动和自主功能的通路。
