Inhibitory glutamate response on cyclic AMP formation in cultured astrocytes.
We examined the effects of glutamate receptor agonists on cyclic AMP (cAMP) formation in cultured astrocytes. L-Glutamate reduced the cAMP formation induced by either isoproterenol (IC50 7 microM) or forskolin without affecting the basal level. Glutamate agonists reduced the cAMP formation in astrocytes with the following rank order of potency: L-glutamate > trans-(+/-)-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) = quisqualate. Pretreatment of astrocytes with pertussis toxin resulted in a partial reduction of the glutamate response and a complete attenuation of the t-ACPD response. These results suggest that astrocytes have another type of metabotropic glutamate receptor which inhibits adenylate cyclase through pertussis toxin-sensitive G-proteins.
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Osaka University, Japan.
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Baba
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Saga
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Hashimoto
D037361:Adenylate Cyclase Toxin; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000378:metabolism*; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists; D007457:Iodine Radioisotopes; D007545:Isoproterenol / Q000494:pharmacology; D037342:Pertussis Toxin; D016318:Quisqualic Acid / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000187:drug effects*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D037361:Adenylate Cyclase Toxin; D018691:Excitatory Amino Acid Antagonists; D007457:Iodine Radioisotopes; D017470:Receptors, Glutamate; D010566:Virulence Factors, Bordetella; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D005576:Colforsin; D016318:Quisqualic Acid; D000242:Cyclic AMP; D037342:Pertussis Toxin; D007545:Isoproterenol