Comparison of early barbiturate and ethanol effects on the CNS

The present article surveys animal studies on the long lasting effects of each (pre and/or neonatal) exposure to barbiturate on brain and behavior. The effects of barbiturate were compared to the known effects of early ethanol administration. Changes in non-neural systems were also mentioned if they had an effect on behavior. Although information on the effect of these two drugs originated from studies which were conducted under different conditions, a pattern of similarity between them is starting to emerge. Both drugs had the ability to destroy even already formed neurons. This ability differentiates them from many other drugs that can destroy only proliferating, migrating, and differentiating brain cells. Barbiturate and ethanol, when given during early development, exerted similar effects on the susceptibility to audiogenic seizures. Both had most of their effect during the neonatal and not the prenatal period. Barbiturate and ethanol were very similar in their ability, when given prenatally, to cause long lasting induction of their hepatic metabolizing enzymes. The fact that early administration of ethanol and barbiturates caused a similar reduction of learning is also well established. Further studies are still needed to settle the issue of brain response to these drugs. While early barbiturate administration caused long lasting changes in brain responses to the drugs, only some of the ethanol studies demonstrated similar effects following early ethanol administration, while other studies showed no effect. In the case of aggression, there may actually be a difference between the action of early barbiturate and ethanol administration. Neonatal administration of ethanol resulted in a long lasting depression of aggression, while similar treatment with barbiturate did not produce statistically significant changes of aggression. Prenatal administration of relatively high levels of ethanol did not affect aggression; low doses of ethanol did enhance aggression.