Open junctions in the endothelium of the postcapillary venules of the diaphragm.
Open junctions in the endothelium of the postcapillary venules of the diaphragm.
复制标题
隔膜后毛细血管内皮中的开放连接处。
DOI：
10.1083/jcb.79.1.27
复制
发表时间：
1978-10
影响因子：
7.8
通讯作者：
Palade, G E
中科院分区：
文献类型：
--
作者：
Simionescu, N;Simionescu, M;Palade, G E
我们以前已经证实，小鼠膈肌细胞周微静脉中约30%的内皮连接开放至约30- 60埃的间隙，并被血红素十肽（H 11 P）（分子直径约20埃）完全渗透。为了估计可以渗透这些路口的分子的大小限制，我们静脉内给予分级示踪剂，并研究了它们的行为在双极微血管领域（BMF）在小鼠膈肌的细胞周小静脉的水平。辣根过氧化物酶（HRP）（分子直径约50 A）仅渗透约50%的小静脉内皮开放连接。通过小静脉连接的流出似乎是适度的，因为示踪剂仍然限制在小静脉周围空间。血红蛋白（Hb，摩尔直径64 × 55 × 50 A）仅渗透少数（小于5%），铁蛋白（摩尔直径110 A）几乎不渗透细胞周小静脉的内皮连接。研究结果表明，在正常条件下，开放的小静脉连接处的渗透分子的大小限制约为60。从BMF适当区域的冷冻断裂制备物的复制品表明，微静脉内皮细胞间连接具有与先前描述的网膜和肠系膜中微血管系统的相应节段相同的组织：不连续的折痕或凹槽，不含或仅由少量膜内颗粒标记。组胺（局部或全身）和5-羟色胺（5-HT）（局部）给药导致毛细血管后小静脉中内皮连接和大示踪颗粒（炭黑）壁内沉积的典型局灶性分离。
We have previously established that approximately 30% of the endothelial junctions in the pericytic venules of the mouse diaphragm are open to a gap of approximately 30--60 A, and are fully permeated by hemeundecapeptide (H11P) (mol diam approximately 20 A). To estimate the size limit for molecules that can permeate these junctions, we have administered graded tracers intravenously and studied their behavior at the level of pericytic venules in bipolar microvascular fields (BMFs) in the mouse diaphragm. Horseradish peroxidase (HRP) (mol diam approximately 50 A) permeated only approximately 50% of the open junctions of the venular endothelium. Outflow through venular junctions appeared to be modest since the tracer remained restricted to the perivenular spaces. Hemoglobin (Hb, mol diam 64 x 55 x 50 A) permeated only a few (less than 5%), and ferritin (mol diam 110 A), practically none, of the endothelial junctions of the pericytic venules. The findings suggest that under normal conditions the size limit for permeant molecules for open venular junctions is approximately 60 A. Replicas of freeze-fracture preparations from appropriate regions in BMF showed that the intercellular junctions of the venular endothelium have the same organization as previously described for the corresponding segments of the microvasculature in the omentum and mesentery: discontinuous creases or grooves either free of or marked by few intramembrane particles only. Administration of histamine (topically or systemically) and 5-hydroxytryptamine (5-HT) (topically) resulted in typical focal separations of the endothelial junctions and intramural deposits of large tracer particles (carbon black) in the postcapillary venules.