Long-term effects of chronic oral Ritalin administration on cognitive and neural development in adolescent wistar kyoto rats

Margery C Pardey, Natasha N Kumar, Ann K Goodchild, Kelly J Clemens, Judi Homewood, Jennifer L Cornish

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)

    Abstract

    The diagnosis of Attention Deficit Hyperactivity Disorder (ADHD) often results in chronic treatment with psychostimulants such as methylphenidate (MPH, Ritalin®). With increases in misdiagnosis of ADHD, children may be inappropriately exposed to chronic psychostimulant treatment during development. The aim of this study was to assess the effect of chronic Ritalin treatment on cognitive and neural development in misdiagnosed "normal" (Wistar Kyoto, WKY) rats and in Spontaneously Hypertensive Rats (SHR), a model of ADHD. Adolescent male animals were treated for four weeks with oral Ritalin® (2 × 2 mg/kg/day) or distilled water (dH2O). The effect of chronic treatment on delayed reinforcement tasks (DRT) and tyrosine hydroxylase immunoreactivity (TH-ir) in the prefrontal cortex was assessed. Two weeks following chronic treatment, WKY rats previously exposed to MPH chose the delayed reinforcer significantly less than the dH2O treated controls in both the DRT and extinction task. MPH treatment did not significantly alter cognitive performance in the SHR. TH-ir in the infralimbic cortex was significantly altered by age and behavioural experience in WKY and SHR, however this effect was not evident in WKY rats treated with MPH. These results suggest that chronic treatment with MPH throughout adolescence in "normal" WKY rats increased impulsive choice and altered catecholamine development when compared to vehicle controls.

    Original languageEnglish
    Pages (from-to)375-404
    Number of pages30
    JournalBrain Sciences
    Volume2
    Issue number3
    DOIs
    Publication statusPublished - 12 Sep 2012

    Keywords

    • methylphenidate
    • adolescent
    • tyrosine hydroxylase
    • chronic administration
    • prefrontal cortex
    • impulsivity
    • impulsive choice

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