Davis D A, Milhorat T H
Anat Rec. 1975 Apr;181(4):779-89. doi: 10.1002/ar.1091810409.
Following intravenous injection, cytochrome c traverses the capillary endothelium of the rat choroid plexus and permeates the perivascular space and the extracellular space between epithelial cells. The tracer is incorporated into pinocytotic vesicles adjacent to the lateral and basal plasmalemmas. Thereafter, cytochrome c is incorporated into multivesicular and dense bodies. Tracerladen vesicles were not found to fuse with the apical plasmalemma and cytochrome c was not discharged into the cerebral ventricles. Acid phosphatase activity of the choroidal epithelium after the administration of cytochrome c was greatly increased and localized in the same intracellular sites shown for cytochrome c. These data suggest that cytochrome c and possibly other proteins that penetrate the choroidal stroma are taken up by the choroidal epithelium and subsequently degraded in lysosomal vesicles. This heterolytic mechanism may be an important means for preventing the entry of certain substances such as proteins into CSF and subsequently into nervous tissue.
静脉注射后，细胞色素c穿过大鼠脉络丛的毛细血管内皮，渗透到血管周围间隙和上皮细胞之间的细胞外间隙。示踪剂被并入与外侧和基底质膜相邻的胞饮小泡中。此后，细胞色素c被并入多囊体和致密体中。未发现载有示踪剂的小泡与顶端质膜融合，细胞色素c也未排入脑室。给予细胞色素c后脉络丛上皮的酸性磷酸酶活性大大增加，并定位于与细胞色素c所示相同的细胞内位点。这些数据表明，细胞色素c以及可能穿透脉络丛基质的其他蛋白质被脉络丛上皮摄取，随后在溶酶体小泡中降解。这种异溶机制可能是防止某些物质如蛋白质进入脑脊液并随后进入神经组织的重要手段。
