Isolated microvessels: the blood-brain barrier in vitro.
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.
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001812:Blood-Brain Barrier; D002199:Capillary Permeability; D002417:Cattle; D002540:Cerebral Cortex / Q000098:blood supply*; D004298:Dopamine / Q000378:metabolism; D066298:In Vitro Techniques; D008833:Microcirculation / Q000502:physiology*; D012160:Retina / Q000098:blood supply*; D013237:Stereoisomerism; D013395:Sucrose / Q000378:metabolism; D013696:Temperature
D000596:Amino Acids; D013395:Sucrose; D004298:Dopamine