title: Glutamate uptake is stimulated by extracellular S100B in hippocampal astrocytes.
abstract: 1.S100B is a calcium-binding protein expressed and secreted by astrocytes, which has been implicated in glial-neuronal communication. Extracellular S100B appears to protect hippocampal neurons against toxic concentrations of glutamate. Here we investigated a possible autocrine role of S100B in glutamate uptake activity. 2. Astrocyte cultures were prepared of hippocampi from neonate Wistar rats. [(3)H] Glutamate uptake was measured after addition of S100B protein, antibody anti-S100B or TRTK-12, a peptide that blocks S100B activity mediated by the C-terminal region. 3.Antibody anti-S100B addition decreased glutamate uptake measured 30 min after medium replacement, without affecting cell integrity or viability. Moreover, low levels of S100B (less than 0.1 ng/mL) stimulated glutamate uptake measured immediately after medium replacement. 4. This finding reinforces the importance of astrocytes in the glutamatergic transmission, particularly the role of S100B neuroprotection against excitotoxic damage.
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
authors.forename: Francine
authors.initials: F
authors.lastname: Tramontina
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Tramontina
authors.forename: Daniela F
authors.initials: DF
authors.lastname: Souza
authors.forename: Marina C
authors.initials: MC
authors.lastname: Leite
authors.forename: Carmem
authors.initials: C
authors.lastname: Gottfried
authors.forename: Diogo O
authors.initials: DO
authors.lastname: Souza
authors.forename: Susana T
authors.initials: ST
authors.lastname: Wofchuk
authors.forename: Carlos-Alberto
authors.initials: CA
authors.lastname: Gonçalves
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002478:Cells, Cultured; D018698:Glutamic Acid / Q000378:metabolism*; D006624:Hippocampus / Q000166:cytology* / Q000378:metabolism; D009414:Nerve Growth Factors / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism*
chemical_list: D009414:Nerve Growth Factors; D018696:Neuroprotective Agents; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579158:S100b protein, rat; D018698:Glutamic Acid