title: Proteins of the brain extracellular fluid: evidence for release of S-100 protein.
abstract: Extracellular protein fractions were obtained (1) by mild, isotonic irrigation of freshly perfused brain tissue; (2) by collection of proteins released into superfusing medium by physiologically viable slices of rat hippocampus; and (3) by sampling the CSF of anesthetized rats. Analysis of the S-100 protein content of these fractions gave values of 2.8, 4.2, and 1.8 micrograms S-100/mg protein, respectively. These values were three- to sixfold higher than the S-100 content of the soluble cytoplasmic protein fractions from the same tissue. This several-fold higher S-100 content of the extracellular protein fractions relative to the intracellular cytoplasmic protein fractions indicates that S-100 is selectively released into the extracellular spaces of the brain. We suggest that the biological function of this CNS protein may involve intercellular transfer.
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D005110:Extracellular Space / Q000032:analysis*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D051379:Mice; D051381:Rats; D009418:S100 Proteins / Q000032:analysis* / Q000134:cerebrospinal fluid / Q000378:metabolism; D013045:Species Specificity
chemical_list: D009418:S100 Proteins