The influence of alpha-adrenergic drugs on catalepsy induced by haloperidol or fluphenazine in rats.

Clonidine (ip) and methoxamine (ivc) inhibit the catalepsy produced by haloperidol or fluphenazine. Naphazoline and xylometazoline antagonize the catalepsy produced by haloperidol, but do not affect significantly that produced by fluphenazine. Phenylephrine did not affect the catalepsy produced by either neuroleptic. The results indicate that drugs stimulating central noradrenergic receptors antagonize the action of compounds blocking the central dopaminergic receptors.