Glutamate production by cultured microglia: differences between rat and mouse, enhancement by lipopolysaccharide and lack effect of HIV coat protein gp120 and depolarizing agents.
Glutamate release from rat and mouse microglia subcultures grown in a serum-free medium was substantially greater in the presence than in the absence of a physiological concentration of glutamine (0.5 mM). Mouse microglia produced and released more glutamate than rat microglia. Glutamate accumulation in the medium increased with time and cell density, which is consistent with the virtual absence of glutamate reuptake. Lipopolysaccharide (LPS; 10-100 ng/ml), HIV coat protein gp120 (0.1-10 nM), high K+ (35 mM) or ATP (150 microM), did not affect glutamate release from cells maintained in serum-free medium. In the presence of 1% dialyzed serum, however, LPS induced a dose- and time-dependent increase in the accumulation of glutamate in the medium, suggesting that, as in other cell types, serum factors are required for LPS binding to its receptors.
Patrizio
M
M
Laboratory of Pathophysiology, Istituto Superiore di Sanità, Rome, Italy.
Levi
G
G
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000096:biosynthesis*; D005973:Glutamine / Q000494:pharmacology; D015699:HIV Envelope Protein gp120 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D017628:Microglia / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D016895:Culture Media, Serum-Free; D015699:HIV Envelope Protein gp120; D008070:Lipopolysaccharides; D005973:Glutamine; D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D011188:Potassium