Metrazol administered subcutaneously at a dose of 80 mg . kg-1 elicited genuine minimal seizures (predominantly clonic) in adult, 45- and 25-day-old rats. The same dose of metrazol resulted in long-lasting generalized tonic-clonic seizures in rats aged 15 days and younger. Eighteen-day-old rats represented a transitory stage in which both types of seizures were present: minor seizures at first and then, after a short resting period, major seizures. A different seizure pattern in young rats was not induced by their higher sensitivity to metrazol, but was caused by the level of neural maturation.

Epilepsy Research in the Institute of Physiology of the Czech Academy of Sciences in Prague

Pentylenetetrazol-induced seizures in rats: an ontogenetic study