Differential effects of cyclooxygenase inhibitors on haloperidol-induced catalepsy

Prostaglandins (PGs) might play a role as putative transmitters or as modulators in the central nervous system (CNS). In the present study, haloperidol (1 mg/kg i.p.)-treated mice showed significant cataleptic behaviour. Naproxen, a nonselective cyclooxygenase (COX) inhibitor, dose-dependently (5 and 10 mg/kg) antagonized the haloperidol-induced catalepsy in mice. Nimesulide, a preferential COX inhibitor, also dose-dependently reduced the cataleptic score in haloperidol treated animals at the first and second hour but not at the third and fourth hour of haloperidol treatment. Rofecoxib, a selective COX-2 inhibitor, did not show any effect on haloperidol-induced catalepsy. The major findings of the present study suggest that PGs might play a significant role in haloperidol-induced catalepsy. The findings of the present study further suggested that COX-1 derived rather than COX-2 derived PGs might play a potential role in haloperidol-induced catalepsy. In conclusions COX inhibitors can be screened as potential drug candidates for the treatment of neuroleptic-induced extrapyramidal side effects (EPS).