DEVELOPMENTAL-CHANGES OF KETAMINE ACTION AGAINST EPILEPTIC AFTERDISCHARGES INDUCED BY HIPPOCAMPAL-STIMULATION IN RATS

Action of ketamine (5-40 mg/kg) was tested against electrically induce d hippocampal afterdischarges (four stimulations in one session; 8 Hz, 15 s) in rats 7, 12, 18, 25 and 90 days old. In control sessions, the re was either stable afterdischarge (AD) duration and wet dog shakes ( WDS) number or there was an increase in ADs' duration with repeated st imulations. Ketamine had dose-dependent and age-dependent effects. In 7-18-day-old rats, ketamine suppressed better WDS number than AD durat ion, with nearly absent action on AD duration in 18-day-old animals. K etamine was equipotent for both phenomena in 25-day-old rats and, in c ontrast, it decreased more AD duration than WDS number in 90-day-old r ats. The data suggest a differentiation induced by ketamine in the exp ression of motor and electrographic phenomena of the experimental seiz ures.