Social isolation and tolerance development to sodium barbital in mice.

The effect of the duration of isolation periods on the development of tolerance to sodium barbital was studied in mice. The HD50 values for pentobarbital-induced hypnosis were higher in all mice that were long-term treated with sodium pentobarbital, whether or not they were isolated or in groups. Diazepam HD50s were higher in mice isolated and long-term treated with sodium barbital for 38 days and in grouped animals treated with the barbiturate for 20 and 30 days. Social isolation for 8 weeks plus 23 days increased the pentobarbital hypnotic dose (HD50). These data show that social isolation increased the rate of tolerance acquisition to sodium barbital by mice.