THE NEUROPHARMACOLOGY OF 2-(o-CHLOROPHENYL)-2-METHYLAMINOCYCLOHEXANONE HYDROCHLORIDE

¹ Parke, Davis & Company, Research Division, Ann Arbor, Michigan

The neuropharmacologic properties of 2-(o-chlorophenyl)-2-methylaminocyclohexanone (CI-581) have been investigated by comparison with those of phencycidine, pentobarbital and mephenesin. Like phencyclidine, it causes excitation in mice at low doses. The two drugs enhance the tail erection in mice from morphine at low doses but will suppress it at higher doses. They differ from pentobarbital and mephenesin in possessing a cataleptic action. Unlike phencycidine, CI-581 induces general anesthesia not only in monkeys but also in mice and pigeons. Whereas phencycidine at high doses will cause convulsions in these three species of animals, CI-581 will not. The excitatory effect of CI-581, like that of phencycidine, was increased in mice by pretreatment with iproniazid. While the duration of phencyclidine anesthesia was increased in monkeys by iproniazid pretreatment, the duration of CI-581 anesthesia was not prolonged in iproniazid-pretreated animals. Resembling mephenesin, CI-581 was found most effective in opposing the convulsive action of p- toluidino-3-propylamino-2-propanol, but was only slightly effective in opposing that of pentylenetetrazol. Differing from mephenesin and pentobarbital, CI-581 was ineffective against convulsions from strychnine. CI-581, at doses producing slight ataxia, was very effective in abolishing the electrically induced tonic extensor seizures in mice, but was capable of markedly suppressing the pentylenetetrazol-induced initial clonic seizures only at anesthetic doses.