Hjelle J T, Baird-Lambert J, Cardinale G, Specor S, Udenfriend S
Proc Natl Acad Sci U S A. 1978 Sep;75(9):4544-8. doi: 10.1073/pnas.75.9.4544.
Isolated bovine retinal and brain microvessels, exhibiting a patent lumen, were used to study the contribution of the microvasculature to the blood-brain and blood-retina barriers. The diffusion marker, sucrose, was taken up slowly by the isolated microvessels in contrast to leucine, tyrosine, and valine which were taken up at a considerably faster rate. Uptake of leucine was temperature dependent but resistant to inhibition by ouabain and sodium azide. The large neutral amino acids exhibited stereospecificity and cross-competition for uptake by the isolated microvessels. The apparent Kms for uptake for tyrosine, leucine, and valine were III micron,133 micron, and 500 micron, respectively.
分离出的具有开放管腔的牛视网膜和脑微血管被用于研究微血管对血脑屏障和血视网膜屏障的作用。与亮氨酸、酪氨酸和缬氨酸相比,扩散标记物蔗糖被分离出的微血管缓慢摄取,亮氨酸、酪氨酸和缬氨酸的摄取速度要快得多。亮氨酸的摄取依赖于温度,但不受哇巴因和叠氮化钠的抑制。大中性氨基酸对分离出的微血管摄取表现出立体特异性和交叉竞争。酪氨酸、亮氨酸和缬氨酸摄取的表观米氏常数分别为111微摩尔、133微摩尔和500微摩尔。