In utero methamphetamine effects: I. Behavior and monoamine uptake sites in adult offspring

Chronic in utero methamphetamine treatment, throughout gestation in rats, resulted in alterations in both behavior and brain monoamine function in the adult offspring. The higher dose of methamphetamine (10 mg/kg/b.i.d.) caused a significant decrease in square crossing and rearing in an open field, as well as a regional increase of serotonin and dopamine uptake sites. In contrast, the lower dose of in utero methamphetamine (2 mg/kg/b.i.d.) resulted in a significant decrease in regional densities of serotonin and dopamine uptake sites, and only decreased rearing behavior. Across treatment groups, there were significant correlations between open-field square crossing activity and the number of uptake sites in specific brain areas. Other measured behaviors, such as the neonate righting reflex and the adult Morris water maze performance, were unaffected by either in utero drug regimen. These results are discussed in terms of the known neurotoxicity of amphetamines and the ability of the immature nervous system to compensate for fetal exposure to methamphetamine.