Locomotor activity and alcohol preference in alcohol-preferring and -nonpreferring rats following neonatal alcohol exposure.

Abstract

Recently, we reported that the alcohol preferring (P) and nonpreferring (NP) rats, bred for differences in alcohol preference, showed different behavioral effects of neonatal alcohol exposure when tested as juveniles. Following neonatal alcohol exposure, the P line showed a greater increase in activity than the NP line relative to their respective controls. In the present study, P and NP rat pups were separated from their mothers and artificially reared from postnatal day (PND) 4 until PND 12. Pups were implanted with intragastric cannulas on PND 4 and fed a stock milk solution every 2 h via an indwelling cannula. One group had alcohol added to the milk diet during the 4 daytime feeds at a dose of 6 g/kg/day on PND 4-7 and a dose of 3 g/kg/day on PNDs 8 and 9. One control group was artificially reared and fed an isocaloric milk solution and a second control group was reared normally with a surrogate dam. Rats were tested as adults (80-day-old) for open-field activity and alcohol preference. Neonatal alcohol exposure caused equivalent increases in activity in P and NP rats. In the ethanol preference test, neither the P nor the NP rats showed any effect of neonatal alcohol treatment although there were large line difference in alcohol preference. These data suggest that the increased susceptibility of young P rats to neonatal alcohol exposure, measured by open-field activity, does not extend to adulthood. Furthermore, neonatal alcohol exposure does not appear to alter alcohol preference in either line.