Klegeris A, Walker DG, McGeer PL. Regulation of glutamate in cultures of human monocytic THP-1 and astrocytoma U-373 MG cells.
J Neuroimmunol 1997;
78:152-61. [PMID:
9307240 DOI:
10.1016/s0165-5728(97)00094-5]
[Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glutamate, an excitatory neurotransmitter, is neurotoxic at high concentrations. Neuroglial cells, including astrocytes and microglia, play an important role in regulating its extracellular levels. Cultured human monocytic THP-1 cells increased their glutamate secretion following 18 and 68 h exposure to the inflammatory mediators zymosan, phorbol myristate acetate (PMA), lipopolysaccharide, interferon-gamma, tumor-necrosis factor-alpha and interleukin-1beta. Cultured astrocytoma U-373 MG cells increased their glutamate secretion following similar exposure to zymosan and PMA. DL-Alpha-aminopimelic acid, an inhibitor of the glutamate secretion system, reduced extracellular glutamate in both cell culture systems, while the high-affinity glutamate uptake inhibitors D-Aspartic acid, DL-threo-beta-hydroxyaspartic acid and L-trans-pyrrolidine-2,4-dicarboxylic acid increased extracellular glutamate in U-373 MG, but not THP-1 cell cultures. In co-cultures of THP-1 and U-373 MG cells, extracellular glutamate levels were increased significantly by the Alzheimer beta-amyloid peptide (1-40) and were decreased significantly by the anti-inflammatory drug dexamethasone. These data indicate that inflammatory stimuli may increase extracellular glutamate while antiinflammatory drugs decrease it.
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