Cornford E M, Varesi J B, Hyman S, Damian R T, Raleigh M J
Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90095, USA.
Exp Brain Res. 1997 Oct;116(3):399-405. doi: 10.1007/pl00005768.
The objective of the present study was to examine the apparent work capacity of one of the two separate membrane systems (the blood-cerebrospinal fluid barrier) that isolate the mammalian brain extracellular fluid (and cerebrospinal fluid, CSF) from plasma. Digitized analyses of electron-microscopic images provided estimates of mitochondrial volumes, which were expressed as a percentage of the cell cytoplasm. We recorded a high mitochondrial content of 12-15% in the cuboidal epithelium of primate choroid plexus, which was consistent in vervet, rhesus, and squirrel monkeys, as well as in baboons. Similarly high mitochondrial contents were observed in the rabbit, rat, and mouse choroid plexus. It has been postulated that the high mitochondrial content of brain endothelium is associated with maintaining the ionic gradients within the central nervous system. We observed that the mitochondrial content of the choroid plexus (where CSF is produced) was slightly higher than in (prior measurements of) the blood-brain barrier (BBB). In addition, surface areas at the apical borders of the choroid plexus epithelia (where the Na+K+ATPase activity has been localized) were increased 7- to 13-fold over the basal borders, in the primate species examined. The observation of high mitochondrial volumes in choroid plexus cells is consistent with the suggestion that increased mitochondrial densities seen in choroidal epithelia and BBB capillaries provide a metabolic work capability for both secretory activities and maintaining ionic gradients across blood-CSF barriers.
本研究的目的是检测将哺乳动物细胞外液（以及脑脊液，CSF）与血浆分隔开来的两个独立膜系统之一（血脑屏障）的表观工作能力。对电子显微镜图像进行数字化分析，得出线粒体体积的估计值，该值以细胞质的百分比表示。我们记录到灵长类脉络丛立方上皮细胞中线粒体含量很高，为12% - 15%，在绿猴、恒河猴、松鼠猴以及狒狒中均如此。在兔、大鼠和小鼠的脉络丛中也观察到了类似的高线粒体含量。据推测，脑内皮细胞的高线粒体含量与维持中枢神经系统内的离子梯度有关。我们观察到脉络丛（产生脑脊液的部位）的线粒体含量略高于血脑屏障（BBB）（之前的测量结果）。此外，在所研究的灵长类动物中，脉络丛上皮细胞顶端边界（已确定Na + K + ATP酶活性所在位置）的表面积比基底边界增加了7至13倍。脉络丛细胞中高线粒体体积的观察结果与以下观点一致，即脉络丛上皮细胞和血脑屏障毛细血管中增加的线粒体密度为分泌活动以及维持血脑屏障的离子梯度提供了代谢工作能力。
