Influence of clonazepam and ethosuximide on ECoG pattern induced by metrazol during ontogenesis in rats.

Metrazol (80 mg/kg s. c.) elicited ECoG episodes of rhythmic activity the shape, frequency and localization of which depended on the age of rats. In 15- and 12-day-old animals there was a progression into sustained ictal activity. Clonazepam (1 mg/kg i. p.) exhibited excellent anti-metrazol action in adult, 25- and 12-day-old rats. The results in 15-day-old animals were inconsistent. Ethosuximide (125 mg/kg i. p.) protected sufficiently only adult and 25-day-old rats. In younger age groups only ictal activity was blocked, while metrazol-induced episodes remained untouched.