Attenuation of maternal behavior in virgin CD-1 mice by methylphenidate hydrochloride

The administration of methylphenidate hydrochloride (MPH) to girls and women has increased in the last decade and the potential for mothers to receive this medication has also increased. Because substances that alter the dopaminergic systems can also disrupt maternal behavior, and MPH acts on dopaminergic neurons, we evaluated the influence of MPH on maternal behavior. The maternal induction paradigm allowed us to assess changes in spontaneous maternal behavior as a result of repeated exposure to MPH without exposing pups to the drug. Virgin female CD-1 mice received MPH (5 mg/kg) or saline daily, starting 3 days before pup exposure, and for the duration of the 10-day test period. Naïve groups of three pups were placed with the female each day and maternal behavior was assessed during 10-minute observation periods 1 h post-injection. MPH-treated females showed significantly less maternal behavior, including reduced pup licking and crouching over pups, compared to saline treated females. MPH-treated females also exhibited higher activity levels than saline treated females. Given the disruption in spontaneous maternal behavior of MPH-treated mice, further research examining the relationship between maternal behavior and MPH exposure is warranted.