The psychopharmacological properties of pinazepam, a new benzodiazepine derivative

The pharmacological differences between the behavioural effects of 7-chloro-1-propargyl-5-phenyl-3H-1,4-benzodiazepin-2-one (pinazepam) and diazepam were investigated in rats. Pinazepam was more than twice as active as diazepam at a dose range between 1.25--10 mg/kg in reducing the conditioned emotional response (CER). Only at doses of 2.5 and 5 mg/kg prevented pinazepam the disruption of the avoidance responses induced by inverting the conditioned stimulus (CS). On the other hand pinazepam was less active than diazepam in reducing the number of avoidance responses in a conditioned avoidance situation. Neither pinazepam nor diazepam disrupted the conditioned responses in a fixed-interval operant behaviour.