Neonatal ethanol exposure: effects on adult behavior and brain growth parameters

Neonatal rats were reared using an artificial feeding technique from postnatal day 4 through 18. On postnatal day 4 through 7, some animals were given ethanol in their milk formula with the remaining animals serving as controls. The ethanol was given in amounts that have been shown to induce microcephaly when animals are examined at 18 days after birth. In this study, on postnatal day 18, all animals were weaned and allowed ad lib food and water until they were sacrificed at 60 days of age. When the animals were 30 days old, they were tested on a battery of behavioral tasks (nose poke, passive avoidance, and open field). No differences were found between the ethanol exposed animals and their controls on passive avoidance or nose poke activity. Ethanol-exposed female animals showed increased activity compared to their controls in the open field. There were no differences in open field activity between the ethanol exposed males and their controls. An examination of brain growth parameters (wet weights, DNA, cholesterol and protein content) showed no difference between the brains of ethanol-exposed males compared to controls at 60 days of age, regardless of brain parameter or brain area studied (forebrain, cerebellum or brainstem). The brains of ethanol-exposed females, however, had considerably less catch-up growth, with the ethanol effect on the cerebellum being very similar to that observed at 18 days of age. The results imply that sex and the time of ethanol exposure may interact to determine the ability of the brain to develop following a neonatal alcohol insult.