Dopamine-like activities of an aminopyridazine derivative, CM 30366: a behavioural study.

The behavioural effects of CM 30366, an aminopyridazine derivative, on dopamine-mediated neurotransmissions, have been studied in mice and rats. CM 30366 induced stereotyped behaviour and antagonized haloperidol-induced catalepsy in rats, after parenteral and oral administration. In 6-hydroxy dopamine (6-OHDA)-lesioned mice, CM 30366 induced contralateral rotations and, when injected before 6-OHDA, protected mice against its neurotoxicity. CM 30366 also provoked contralateral rotations when injected directly into the mouse right striatum. After parenteral injection, CM 30366 slightly increased motility in mice, at least at low doses. The stereotypies and rotations (after intrastriatal injection) induced by CM 30366 were antagonized by haloperidol, alpha-methyl-p-tyrosine and reserpine. The effects of CM 30366 were compared to those of direct and indirect dopamine-like drugs. Bromocriptine induced a behavioural profile, which in most aspects, was qualitatively and quantitatively similar to that of CM 30366. Apomorphine was found slightly more potent than CM 30366, but in contrast to the latter, apomorphine-induced stereotypies were insensitive to alpha-methyl-p-tyrosine or reserpine. (+)-Amphetamine and nomifensine were less potent than CM 30366, and unlike CM 30366, induced ipsilateral rotations in 6-OHDA-lesioned mice. These results indicate that CM 30366 is a potent atypical dopamine-like drug of potential therapeutic usefulness.