Decreased brain weights in rats after long-term barbital treatments

To study dependence on barbiturates, rats were in three experiments given a solution of barbital as their only drinking fluid for periods around 30 weeks. The animals were sacrificed after abstinence periods of up to 30 days and the brains were weighed. Compared with untreated controls the barbital treated animals in these experiments consistently had reduced wet brain weights. This reduction was not restituted after an abstinent period of 30 days. The decrease did not seem to be secondary to a reduced body weight. The decrease in brain weight found throughout the abstinence period was not influenced by changes in water intake.In a 4th experiment 12 weeks of barbital treatment caused a similar slightly smaller reduction in wet brain weight. Since there was no difference in water content the dry weight was also reduced. The possibility that this finding is related to the brain atrophy found in humans after long-term ethanol abuse is pointed out.