Does status epilepticus influence the motor development of immature rats?

Purpose: To study the effect of severe status epilepticus (SE) on the motor development of rats. Methods: SE was induced in 12-day-old rats (P12 group) and 25-day-old rats (P25 group) using the Lithium-pilocarpine model. Seizures were interrupted after 2 hours by paraldehyde with an intraperitoneal dose of 0.3 or 0.6 mL/ kg, respectively. Starting 3 days after SE, all animals were repeatedly exp osed to a battery of motor and behavioral tests, including the bar-holding test, rotarod test, and open field test. Results: In P12, animals, motor impairment occurred 2 months after SE, when significantly worse performance in the rotarod test was found. No differen ce between controls and experimental rats was found in any other test used. In contrast, P25 animals were significantly poorer in the bar-holding test from postnatal day 34 until adulthood. In open field study, P25 rats were found to be hyperactive during the whole period of testing, whereas P12 ani mals exhibited an initial period of hypoactivity (in the first test) that w as replaced by hyperactivity that lasted until 2 months of age. In the last test performed at the age of 98 days, experimental P12 animals were again less active than age-matched controls. Conclusions: Animals of both age groups exhibited permanent changes of moto r performance; however, both the pattern and the time course of these chang es was related to age when SE was elicited.