Postnatal methadone exposure does not prevent prenatal methadone-induced changes in striatal cholinergic neurons

On postnatal day 4, rats exposed to methadone prenatally but fostered to control darns, as well as those fostered to darns treated with methadone, exhibited significant reductions in striatal acetylcholine (ACh) content. This suggests that neonatal withdrawal from methadone is not responsible for the effects of prenatal exposure on cholinergic development in the early perinatal period. The effects of perinatal exposure to methadone on serotonin (5HT) and dopamine (DA) metabolism do not appear to be strictly related to changes in ACh content. Although prenatal exposure reduces 5-hydroxyindole acetic acid (5HIAA) content, changes in SPIT content prevent significant changes in the ratio 5HIAA/5HT. Pups exposed to methadone only prenatally (withdrawal group) exhibited a decreased DOPAC/DA ratio, whereas pups in the treatment group exposed to methadone both pre- and postnatally exhibited an increased DOPAC/DA ratio.