Potentiation of pentobarbital hypnosis by nitrodiphenyl-aminoisothiocyanate

The duration of hypnosis of pentobarbital was significantly prolonged when mice or rats were pretreated with NDIT in a dose of ≥160 or≥320 mg/kg ig, respectively, and to some extent, there was a relationship between the dose and the potentiating action by NDIT. The potentiating action exhibited within 24 and 72 h after ig NDIT in mice and rats, respectively. NDIT increased the % of mice which fell asleep by a subhypnotic dose of pentobarbital and prolonged the duration of hypnosis of barbital. Rectal temperature in rats, rate of biotransformation of pentobarbital in mice and plasma t1/2 of pentobarbital in rats were not affected by NDIT. The average brain pentobarbitai concentration of the mice treated with NDIT was significantly lower than that of the control mice when the righting reflex just restored. These results indicate that the sensitivity of the brain to pentobarbital is increased by NDIT which may potentiate the CNS action of barbiturates.