BLOOD-EYE BARRIERS IN THE RAT - CORRELATION OF ULTRASTRUCTURE WITH FUNCTION
BLOOD-EYE BARRIERS IN THE RAT - CORRELATION OF ULTRASTRUCTURE WITH FUNCTION
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DOI：
10.1002/cne.903400409
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发表时间：
1994-02-22
影响因子：
2.5
通讯作者：
TUOR, UI
中科院分区：
文献类型：
--
作者：
STEWART, PA;TUOR, UI
通过测量血管示踪剂C-14-α-氨基异丁酸从血液到组织的转移来评估大鼠眼睛和大脑中不同血管床的功能。在灌流固定的、年龄匹配的组织的电子显微镜下测量血管孔密度，以确定示踪剂转移的差异是否与超微结构的差异平行。视网膜中的示踪剂转移大约是同一动物大脑中示踪剂转移的四倍。冷α-氨基异丁酸的加入没有改变转移常数，表明视网膜血管的运输是不饱和的，并表明，就像在大脑中一样，运输是被动扩散的结果。在超微结构上，视网膜血管内皮细胞间连接和内皮小泡密度较高，这两者都表明血管通透性较高。然而，作为血脑屏障第二道防线的周细胞，在视网膜中的数量大约是脑中的四倍，我们认为在视网膜中，它们起到了补偿更具渗透性的内皮屏障的作用。睫状体血管有较高的示踪剂转移，可能是由于其壁上的开窗所致。虹膜血管的示踪剂转运量相对较低，与视网膜相似，尽管虹膜血管内皮细胞间连接的一部分存在扩张的连接裂隙，提示存在开放的细胞旁通道。然而，虹膜和睫状体都可能失去对前房液体的示踪，导致我们低估了这些部位的血管通透性。(C)1994年Wiley-Liss，Inc.
The function of different vascular beds in the rat eye and brain was evaluated by measuring the transfer of a vascular tracer, C-14-alpha-amino-isobutyric acid, from blood to tissue. The density of vascular pores was measured in electron micrographs of perfusion-fixed, age-matched tissue to determine whether the differences in tracer transfer were paralleled by differences in ultrastructure. Tracer transfer in retina was approximately four times that in brain of the same animal. The transfer constant was not changed by the inclusion of cold alpha-amino-isobutyric acid, showing that transport across retinal vessels is not saturable, and indicating that, as in brain, transport is due to passive diffusion. Ultrastructurally, retinal vessels have a higher density of interendothelial junctions and of endothelial vesicles, both of which suggest higher vascular permeability. However, pericytes, which contribute to a second line of defence in the blood-brain barrier, are approximately four times as numerous in retina as in brain, and we suggest that in the retina, they act to compensate for a more permeable endothelial barrier. Ciliary body vessels had a high transfer of tracer, probably as a consequence of the fenestrations in their walls. Iridial vessels had a relatively low transfer of tracer, similar to that in retina even though a proportion of the interendothelial junctions in iridial vessels had expanded junctional clefts suggestive of open paracellular channels. However, both iris and ciliary body may lose tracer to the anterior chamber fluid, leading us to underestimate the vascular permeability in these sites. (C) 1994 Wiley-Liss, Inc.