Zahs K R, Wu T
Department of Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.
J Comp Neurol. 2001 Jan 8;429(2):253-69. doi: 10.1002/1096-9861(20000108)429:2<253::aid-cne6>3.0.co;2-s.
Astroglia are interposed between the cerebral vasculature and neurons, where they may mediate the transfer of substances from the circulation to neurons and couple changes in neuronal activity to changes in cerebral blood flow. The retina is a particularly advantageous model system for studying glial-vascular interactions in situ. Confocal microscopy and three-dimensional image reconstruction were used to study the anatomical relationships between glia and the surface vasculature in retinas acutely isolated from adult pigmented rats. Retinas were immunostained using antibodies directed against the basal lamina surrounding the vasculature as well as antibodies directed against glial fibrillary acidic protein. Surface vessels of all calibers were contacted by the processes of astrocytes. The vitreal surfaces of the large retinal vessels were covered by a meshwork of immunoreactive astrocyte processes of a variety of shapes, whereas the scleral surfaces of the vessels were supported by thick bundles of astrocyte processes. In addition, glial cells were filled intracellularly with the gap junction-permeable tracers Lucifer yellow and Neurobiotin. Intracellular fills clearly demonstrated the presence of astrocytes with somata that were closely apposed to the large retinal vessels. Tracer-filled astrocytes displayed a variety and complexity of shapes that was not apparent in immunostained material. Gap junctional coupling was stronger between astrocytes adjacent to the same artery than between periarterial astrocytes and astrocytes located away from arteries. Significantly fewer Müller cells were labeled when Neurobiotin was injected into astrocytes associated with arteries than when Neurobiotin was injected into astrocytes that were distant from arteries.
星形胶质细胞介于脑血管系统和神经元之间，在那里它们可能介导物质从循环系统向神经元的转运，并将神经元活动的变化与脑血流量的变化联系起来。视网膜是研究原位胶质-血管相互作用的一个特别有利的模型系统。利用共聚焦显微镜和三维图像重建技术，研究了从成年有色大鼠急性分离的视网膜中胶质细胞与表面血管系统之间的解剖关系。用针对血管周围基膜的抗体以及针对胶质纤维酸性蛋白的抗体对视网膜进行免疫染色。所有管径的表面血管都有星形胶质细胞的突起与之接触。大的视网膜血管的玻璃体表面被各种形状的免疫反应性星形胶质细胞突起网络覆盖，而血管的巩膜表面则由厚束状的星形胶质细胞突起支撑。此外，胶质细胞在细胞内充满了可透过缝隙连接的示踪剂荧光黄和神经生物素。细胞内填充清楚地显示了存在与大的视网膜血管紧密相邻的体细胞的星形胶质细胞。被示踪剂填充的星形胶质细胞呈现出各种形状和复杂性，这在免疫染色材料中并不明显。与同一动脉相邻的星形胶质细胞之间的缝隙连接耦合比动脉周围星形胶质细胞与远离动脉的星形胶质细胞之间的耦合更强。当将神经生物素注入与动脉相关的星形胶质细胞时，被标记的Müller细胞明显少于将神经生物素注入远离动脉的星形胶质细胞时。
