Neuropharmacology of a new psychotropic 2,3-benzodiazepine.

1-(3-Chlorophenyl)-4-methyl-7,8-dimethoxy-5H-2,3-benzodiazepine (GYKI 51189) is a new analogue of tofisopam. Due to the novel chemical structure this molecule displays a peculiar spectrum of pharmacological activity. In many respects tofisopam and its new analogue differ from the traditional 1,4-benzodiazepines, e.

Morphine and [D-Met2,Pro5]enkephalinamide do not show specific neuroleptic activity.

Several conventionally used in vivo pharmacological assays were applied to examine whether morphine (M) and a potent enkephalin analogue, [D-Met2,Pro5]enkephalinamide (DMPEA) have haloperidol (H)-like neuroleptic activity. The apomorphine (A)-induced stereotypy and the conditioned reflex activity were inhibited by extremely low doses of H, while somewhat higher doses were needed to induce catalepsy or to suppress the A-elicited turning behaviour in rats with unilateral nigral lesion. M produced these effects only in doses higher than needed for analgesia.