Possible role of cGMP in excitatory amino acid induced cytotoxicity in cultured cerebral cortical neurons.
Using cultured cerebral cortical neurons at mature stages (9 days in culture, d.i.c.) it was demonstrated that glutamate, NMDA (N-methyl-D-aspartate) and to a lesser extent KA (kainate) increase the intracellular cGMP concentration ([cGMP]i) whereas no such effect was observed after exposure of the cells to QA (quisqualate) and AMPA (2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionate). No effect of glutamate, NMDA and KA was observed in immature neurons (2 d.i.c.). The pharmacology of these cGMP responses was investigated using the glutamate antagonists APV (2-amino-5-phosphonovalerate) with selectivity for NMDA receptors, CNQX (6-cyano-7-nitro-quinoxaline-2,3-dione) with selectivity for non-NMDA receptors and the novel KA selective antagonists AMOA (2-amino-3-[3-(carboxymethoxy)-5-methylisoxazol-4-yl]propionate) and AMNH (2-amino-3-[2-(3-hydroxy-5-methylisoxazol-4-yl)methyl-5-methyl-3- oxoisoxazolin-4-yl]propionate). In addition, the cytotoxicity of glutamate, NMDA and KA was studied and found to be enhanced by addition of the non-metabolizable cGMP analogue 8-Br-cGMP. On the contrary, the toxicity of QA and AMPA was not affected by 8-Br-cGMP. Pertussis toxin augmented the toxicity elicited by glutamate, NMDA, KA and QA but not that induced by AMPA. On the other hand, only glutamate and KA induced toxicity was potentiated by cholera toxin, which also enhanced the stimulatory effect of glutamate and NMDA but not that of KA on the cellular cGMP content. The toxicity as well as the effects on intracellular cGMP levels could be antagonized by the specific excitatory amino acid (EAA) antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Biological Sciences, Royal Danish School of Pharmacy, Copenhagen.
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Frandsen
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Andersen
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Schousboe
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D016923:Cell Death / Q000187:drug effects*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D002772:Cholera Toxin / Q000494:pharmacology; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000494:pharmacology / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D007051:Ibotenic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D007608:Kainic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology; D051379:Mice; D016202:N-Methylaspartate / Q000037:antagonists & inhibitors / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D037342:Pertussis Toxin; D016318:Quisqualic Acid / Q000494:pharmacology; D013997:Time Factors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
D000596:Amino Acids; D018691:Excitatory Amino Acid Antagonists; D005971:Glutamates; D010566:Virulence Factors, Bordetella; D007051:Ibotenic Acid; C016276:8-bromocyclic GMP; D018698:Glutamic Acid; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D016318:Quisqualic Acid; D002772:Cholera Toxin; D037342:Pertussis Toxin; D006152:Cyclic GMP; D007608:Kainic Acid