ANTICONVULSANT ACTIVITY OF MELATONIN AGAINST SEIZURES INDUCED BY QUINOLINATE, KAINATE, GLUTAMATE, NMDA, AND PENTYLENETETRAZOLE IN MICE

Melatonin was tested in an ongoing attempt to find the endogenous anta gonists of quinolinic acid, an endogenous convulsant. Among a great nu mber of metabolites that have been tried before, only a few were found (cerulein and quinaldic acid in mice and kynurenic acid in rats). In SHR (bred from Swiss) male mice, intracerebroventricular (i.c.v.) pret reatment with melatonin (1.25-10.0 mu g) attenuated (in the descending order of potency) the convulsant effect of i.c.v. administered kainat e, quinolinate, glutamate, N-methyl-D-aspartate, and pentylenetetrazol e. Melatonin was ineffective against i.p. administered pentylenetetraz ole. Systemically (intraperitoneal, i.p.) administered melatonin (12.5 -100.0 mg/kg) attenuated the convulsant effect of quinolinate, while t he action of other convulsants used remained unaltered. It is suggeste d that melatonin could be tried against grand mal seizures in epilepti c patients.