Certain Aspects of Drug Distribution to Brain
The wall of the general capillary (tissues other than brain) is freely permeable to all small molecules but the brain capillary wall, the blood-brain barrier (BBB), is impermeable to many small molecules but permeable to certain others. The fundamental difference between these quite different capillary permeability characteristics is diagrammed in Fig. 1. In general capillaries, blood plasma solutes exchange with the more stationary pericapillary extracellular fluid (ECF) largely by diffusion through clefts between the cells making up the capillary wall. This exchange is, accordingly, via extracellular pathways.
KeywordsCapillary Wall Brain Uptake Relative Affinity Tritiated Water Capillary Cell
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