In studying a model inflammatory lesion in the nervous system, such as that of EAE (experimental autoimmune encephalomyelitis), or a naturally occurring lesion in man, such as the plaque of MS (multiple sclerosis), we attempt to establish the presence and significance of one or more standard immunopathologic mechanisms (Boese, ed., 1980; Waksman, 1981). These were first distinguished over a half century ago, but the detailed cellular and molecular events underlying each are still in the process of elucidation.
The term BBB is used to describe the restricted movement of various metabolically important micro- and macro-molecules essentially soluble(solutes), between blood and brain. The function of the BBB rests at the level of endothelial cells (ECs) and results from their special ultrastructural and biochemical properties (6,8,9). Although this barrier is comprised of brain microvessels, choroid plexus epithelium and arachnoid membrane, our main attention will be focused on microvessels (capillaries, precapillary arterioles and postcapillary venules) where extensive processes of exchange of various metabolites between blood and brain parenchyma take place.
