Outcome of status epilepticus in immature rats varies according to the paraldehyde treatment.

Purpose: To test effects of paraldehyde on behavioral outcome of status epilepticus (SE) in developing rats.

Methods: Motor SE was induced by LiCl-pilocarpine in rats on postnatal (P) day 12 or 25. Two hours after SE onset, animals were injected with a single dose of paraldehyde (0.07 and 0.3 ml/kg in the P12 group and 0.3 and 0.6 ml/kg in the P25 group). Effects on seizure severity and mortality were evaluated. Growth of animals and their motor abilities were monitored until the adulthood. Three months after SE, cognitive abilities were tested by using the Morris water maze.

Results: Both tested doses of paraldehyde equally affected motor seizures. Convulsions continued until the paraldehyde administration, but then they quickly subsided in all groups. During the subsequent 24 h, occasional clonic seizures occurred in P25 animals treated with the lower dose of paraldehyde. Only hyperactivity and/or automatisms were observed in the other experimental groups. Mortality was not affected by the dosage of paraldehyde. The higher dosage of paraldehyde improved recovery after SE in both age groups. No difference was found in motor abilities between controls and SE animals, except shortening of time spent on the rod in the rotarod test in the P12 group. In P25 rats, treatment with a higher dosage of paraldehyde improved learning abilities compared with the lower dosage. In the P12 group, animals treated with the lower dosage exhibited slightly impaired learning compared with controls and animals receiving the higher dosage.

Conclusions: Paraldehyde injected 2 h after SE onset modulates long-term outcome in immature rats in a dose-related manner.