Microencephaly and selective decreases in cerebellar Purkinje cell numbers following combined exposure to ethanol and methadone during rat brain development.

This study evaluated the neuroanatomical effects of combined ethanol and methadone exposure on cerebellar development. Ethanol, methadone or a combination of both drugs was delivered twice daily to rat pups using intra-gastric intubation from postnatal day 6 (PN6) to PN10 inclusive. The intubated control group (IK) received equal volumes of isocaloric vehicle. Purkinje cell numbers in cerebellar lobules I-X were quantified from midsagittal sections of the cerebellar vermis at PN11. Deficits of 15-23% in body, total brain, cerebrum, cerebellum and brainstem weights were exhibited for the ethanol/methadone-treated (IEM) group compared to IK. Purkinje cell deficits resulting from IEM treatment were found in lobules VI through X compared to IK with significant decreases of 31 and 23%, respectively, for lobules VIII and X. In contrast, neither ethanol nor methadone exposures under these treatment conditions caused cerebellar deficits.