Critical periods for the effects of alcohol exposure on brain weight, bodyweight, activity and investigation

Using an animal model of fetal alcohol syndrome - which equates peak blood alcohol concentrations across different developmental periods - critical pe riods for the effect of alcohol on brain weight, activity and investigative behavior were examined. The periods of alcohol exposure were from gestatio nal day (GD) 1 through 10, GD 11 through 22, postnatal day (PD) 2 through 1 0, or all three periods combined. The critical period of alcohol exposure f or an increase in activity in juveniles was GD 11 through 22. This pattern was not seen in the same animals in adulthood; instead, increases in both a ctivity and investigation were seen in animals exposed from PD 2 through 10 and not seen in animals exposed during all three periods combined. Brain w eight was reduced by alcohol exposure from GD 11 through 22, PD 2 through 1 0 and all three periods combined. The period from PD 2 through 10 was the o nly period when the brain weight to body weight ratio was reduced. In concl usion, exposure to alcohol during the periods in the latter half of gestati on or early postnatal period seem to have the most deleterious effects on t he brain, activity and investigation in the rat. In addition, the effects o f alcohol exposure over both the prenatal and postnatal period cannot be ea sily predicted from the effects of shorter periods of exposure. (C) 2000 El sevier Science B.V. All rights reserved.