ANTINOCICEPTIVE ACTIVITY OF SODIUM VALPROATE IN MICE AFTER CHRONIC TREATMENT

1. Mice were given sodium valproate (0.71%) in the drinking fluid for 21 days. The antinociceptive activity, locomotor activity and body tem perature changes were recorded at 7, 14 and 21 days. The possible carr yover antinociceptive effects were also determined after valproate wit hdrawal for up to 3 days after 7, 14- and 21 day treatment. 2. The ant inociceptive activity was present only on days ?, 14 and 21 and, on wi thdrawal of the drug, the antinociceptive activity disappeared. 3. Thu s, with this regimen of valproate administration, there was no persist ent antinociceptive activity (carryover effect). There were essentiall y no effects of valproate on the locomotor activity and body temperatu re of mice. The antinociceptive effects were due to the presence of th e drug and disappeared on varproate's withdrawal. (C) 1997 Elsevier Sc ience Inc.