Glutamate-induced swelling of cultured astrocytes is mediated by metabotropic glutamate receptor.
The effects of glutamate and its agonists and antagonists on the swelling of cultured astrocytes were studied. Swelling of astrocytes was measured by [3H]-O-methyl-D-glucose uptake. Glutamate at 0.5, 1 and 10 mmol/L and trans-1-aminocyclopentane-1, 3-dicarboxylic acid (trans-ACPD), a metabotropic glutamate receptor (mGluR) agonist, at 1 mmol/L caused a significant increase in astrocytic volume, whereas alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA) was not effective. L-2-amino-3-phosphonopropionic acid (L-AP3), an antagonist of mGluR, blocked the astrocytic swelling induced by trans-ACPD or glutamate. In Ca(2+)-free condition, glutamate was no longer effective. Swelling of astrocytes induced by glutamate was not blocked by CdCl2 at 20 mumol/L, but significantly reduced by CdCl2 at 300 mumol/L and dantrolene at 30 mumol/L. These findings indicate that mGluR activation results in astrocytic swelling and both extracellular calcium and internal calcium stores play important roles in the genesis of astrocytic swelling induced by glutamate.
Beijing Neurosurgical Institute, China.
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Yuan
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Wang
D000818:Animals; D001253:Astrocytes / Q000187:drug effects*; D048429:Cell Size; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D003620:Dantrolene / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000502:physiology*
D005971:Glutamates; D018094:Receptors, Metabotropic Glutamate; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D003620:Dantrolene