Induction and blockade of epileptic foci by intracerebral injection of glutamatergic agonists and antagonists in frerly moving cats.
The aim of the present work was to test in adult cats the capability of three glutamatergic agonists, NMDA, AMPA and ACDP as epileptogenic agents. Drugs were microinjected in amygdala or hippocampus, and once generated an epileptic focus three selective glutamatergic antagonists NMDA, CNQX and MCPG, were tested. Before and after injection both the EEG and the behavior were continuously monitored. The results were as follows: 1) AMPA showed a greater capability than NMDA or ACPD to generate a chronic epileptic focus; 2) AMPA elicited a greater epileptogenic effect in hippocampus than in amygdala; NMDA had similar epileptogenic effect in both cited structures, and ACPD had not effect; 3) of the three glutamatergic antagonists used to block a long lasting focus, the most effective one was CNQX, which showed a greater effect in hippocampus than in amygdala; 4) comparison between the epileptogenic effect of AMPA and kainic acid (first paper) in the same structure, showed that kainic acid is about 15 fold more epileptogenic. A discussion of the probable mechanisms of these results was undertaken.
Motles
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Instituto de Ciencias Biomédicas, Programa de Fisiopatología, Facultad de Medicina, Universidad de Chile.
Cartier
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Infante
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D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000679:Amygdala / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002415:Cats; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004594:Electrophysiology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005260:Female; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008845:Microinjections; D016202:N-Methylaspartate / Q000494:pharmacology; D018696:Neuroprotective Agents / Q000494:pharmacology; D012640:Seizures / Q000139:chemically induced* / Q000378:metabolism; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018696:Neuroprotective Agents; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid