Neonatal methylphenidate does not impair adult spatial learning in the Morris water maze in rats.

Methylphenidate (MPD) is the most prescribed drug for attention deficit hyperactivity disorder. Licit and illicit use also occurs during pregnancy, however the effects from this use on offspring development are unknown. To model late gestational exposure, Sprague-Dawley litters were treated with 0, 5, 10, 20, or 30mg/kg×4/day every 2h with MPD on postnatal days 11-20 (within-litter design; days chosen to be comparable to human third trimester brain development). During treatment, body weights were decreased in MPD-treated groups; weight recovery occurred in all but the MPD-30 group by start of testing. MPD-treated rats showed no changes in anxiety (elevated zero maze), swimming ability (straight channel swimming), or spatial learning/reference memory (Morris water maze). MPD does not appear to pose a risk to these CNS functions after exposure during a stage of rat development analogous to third trimester human brain development.