High glutamate decreases S100B secretion stimulated by serum deprivation in astrocytes.
S100B is a calcium-binding protein expressed and secreted by astrocytes, playing a neurotrophic role in neighboring cells. A protective role of the S100B against glutamate-induced excitotoxicity has recently been proposed. We investigated S100B secretion in rat hippocampal astrocytes exposed to high concentrations of glutamate during serum deprivation (stimulated condition) or not (basal condition), for 30 min. Glutamate at 1 mM had no effect on basal secretion of S100B, but it decreased S100B secretion in serum-deprived astrocytes after 1 h. Secretion was inhibited by Rp-cAMPS or H89. In addition, serum deprivation was accompanied by a transitory increase of intracellular content of cAMP. Our results suggest that high levels of glutamate in a serum-deprived condition could impair S100B secretion from hippocampal astrocytes.
Gonçalves
Daniela
D
Departmento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos, Porto Alegre, Brazil.
Karl
Juliana
J
Leite
Marina
M
Rotta
Liane
L
Salbego
Christianne
C
Rocha
Elizabete
E
Wofchuk
Susana
S
Gonçalves
Carlos-Alberto
CA
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D018698:Glutamic Acid / Q000494:pharmacology*; D009414:Nerve Growth Factors / Q000378:metabolism*; D009498:Neurotoxins / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins
D002135:Calcium-Binding Proteins; D016895:Culture Media, Serum-Free; D009414:Nerve Growth Factors; D009498:Neurotoxins; D011500:Protein Synthesis Inhibitors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579158:S100b protein, rat; D018698:Glutamic Acid; D003513:Cycloheximide; D000242:Cyclic AMP