Effect of maternally administered methadone on discrimination learning of rat offspring.

Shape discrimination learning by four groups of 150-day-old Sprague-Dawley rats was studied. The groups were the offspring of mothers on the following schedules: (1) prenatal and postnatal methadone, (2) prenatal methadone and postnatal saline, (3) prenatal and postnatal methadone, and (4) prenatal and postnatal saline. The hypothesis investigated was that the methadone groups would show a deficit in learning when compared to the saline-control group. This hypothesis was upheld for the prenatal methadone group and the postnatal methadone group.