Effect of prenatal alcohol exposure on neonatal sleep-wake behaviour and adult alcohol consumption in the AA and ANA rat lines.

To study the role of genetic factors in the effects of prenatal alcohol exposure on behaviour, dams of two rat lines developed to differ in voluntary alcohol intake, alcohol-preferring (AA) and alcohol-avoiding (ANA) rats were given a 5-10% alcohol solution mixed with a 1% sucrose solution as a sole drinking liquid throughout gestation. Sleep-wake behaviour of the offspring was studied at the ages of 7, 14 and 20 days, using a movement-sensitive mattress. In ANA rats, sleep recordings showed that prenatal alcohol exposure increased the percentage of waking but decreased the percentage of active sleep. Sleep-wake behaviour of the AA rats was not affected by alcohol exposure in utero. Prenatal alcohol exposure did not change open field behaviour in 1 month old rats, except that the alcohol-exposed AA rats' defaecation was decreased. When rats were 3 months old, voluntary intake of 10% (v/v) alcohol increased for alcohol-exposed ANA rats and decreased for alcohol-exposed AA rats as compared to the controls. The results indicate that AA rats may compensate for the effects of prenatal alcohol exposure on behaviour, whereas offspring of the alcohol-exposed ANA dams suffer from severe behavioural disturbances. These findings further suggest that genetic factors are responsible for the differences in the susceptibility of rat foetuses to alcohol-induced long-term effects on behaviour.