Nursing experiences with an alcohol-intoxicated rat dam counteract appetitive conditioned responses toward alcohol.

BACKGROUND: Infant rats detect small amounts of alcohol (175 mg%) that are present in maternal milk whenever the dam is moderately intoxicated with alcohol. Interaction with an alcohol-intoxicated mother during the first 2 weeks of life facilitates the preweanling's subsequent discrimination of alcohol's orosensory attributes and produces conditioned aversion to alcohol. The present study further analyzed the hedonic content of infantile alcohol memories established in the nursing context by testing the interaction between experiences with an alcohol-intoxicated dam and learning procedures aimed at establishing an appetitive conditioned response toward alcohol. METHODS: Experiment 1 was to determine appropriate parameters to establish a reliable conditioned preference for alcohol in 16-day-old infants. For conditioning, intraorally infused sucrose solution (appetitive reinforcer) was paired with alcohol's orosensory cues derived from an acute state of alcohol intoxication (3 g/kg). Two control groups included an unpaired condition and a group given sucrose after water intubation. Infants then were evaluated in an alcohol intake test. Relative to control animals, a reliable conditioned preference for alcohol was registered in paired pups. In experiment 2, these conditioning procedures were applied to infant rats which, before conditioning, suckled from dams subjected to a 2.5 g/kg alcohol dose (intragastric) or from water-treated females during postpartum days 3, 5, 7, 9, 11, and 13. RESULTS: Experiment 2 showed that maternal treatment significantly affected the establishment of conditioned preferences for alcohol. Whereas pups reared by control dams exhibited reliable appetitive conditioning to alcohol, infants raised by alcohol dams completely failed to develop appetitive conditioning. CONCLUSIONS: The present results suggest that alcohol-related memories generated via infantile interactions with an intoxicated dam counteract subsequent conditioning of alcohol ingestion. In conjunction with prior studies, it is concluded that alcohol-related nursing experiences are capable of promoting alcohol memories with a negative hedonic content.