A SLIGHT ANTICONVULSANT EFFECT OF CNQX AND DNQX AS MEASURED BY HOMOCYSTEINE-INDUCED AND QUISQUALATE-INDUCED SEIZURES

CNQX and DNQX are compounds that have recently been reported to show potent non-NMDA excitatory amino acid receptor antagonist activity. Effects of these compounds on seizures induced by homocysteine thiolactone and quisqualic acid were studied in order to examine the pharmacological properties of these compounds. In a dosage of 1.16 μg intracerebroventricularly (ICV), CNQX prolonged the latency to the onset of quisqualate-, but not homocysteine-induced seizures. DNQX was not effective when given either ICV or systemically, although a 3.78 μg dose of DNQX given ICV markedly increased the variability in latency to seizure onset, suggesting a combination of pro- and anticonvulsant effects. Higher dosages of both CNQX and DNQX induced seizure-like activity after ICV injection. These data confirm that CNQX has pharmacological effects corresponding to its effects on cellular responses to quisqualate and kainate agonists, but these effects are weak and may limit its usefulness as a pharmacological tool. © 1990.