Effects of early postnatal alcohol exposure on learning in the developing rat: Replication with intubation method of delivery

Early postnatal exposure to alcohol during early development produces defic its in learned persistence, as reflected in the partial reinforcement extin ction effect (PREE) in weanling rats, and deficits memory-based learning, a s shown by patterned single alternation (PSA) discrimination learning in pr eweanling rats. We report a partial replication of these effects using the intubation method instead of artificial rearing. Rat pups were intubated on ce per day with 4.5 g/kg/day alcohol in a milk-based diet or control diet o n postnatal days (PNDs) 4 to 9, and then assessed for the PREE on PNDs 20 a nd 21 or PSA learning on PNDs 17 and 18. Compared with previous artificial rearing reports, the intubation method produced healthier and heavier pups, and yielded a consistently lower and less variable blood alcohol levels. E ven with the lower alcohol levels, intubation with alcohol eliminated the P REE. Intubation with alcohol had a weaker but still detrimental effect on P SA learning. These results suggest that alcohol exposure during development can produce behavioral deficits in the absence of the more severe effects on brain and body growth typically associated with fetal alcohol syndrome.