ABSTRACT
Department of Pharmacology, Hokkaido University School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo 060-8638, Japan Department of Basic Sciences, Japanese Red Cross Hokkaido College of Nursing, Kitami 090-0011, Japan
Abstract-Attention-deficit/hyperactivity disorder (AD/HD) is defined as a developmental disorder, manifested by inattention and/or hyperactivity-impulsivity. Neuropsychological studies suggest impaired cognitive function including working memory. 3-5% of school-aged children show signs of this disorder with male predominance. This article provides an overview of the symptomatic relevance of juvenile stroke-prone spontaneously hypertensive rats (SHRSP) as an animal model of AD/HD. To characterize behavioral alterations, i.e. hyperactivity-impulsivity and/or inattention, SHRSP were diagnosed according to motor activity, as well as emotional and cognitive behaviors with or without methylphenidate, a first choice drug for AD/HD therapy. Ambulatory and rearing activities in the open-field environment were significantly higher in SHRSP than in Wistar-Kyoto rats. In the elevated plus-maze task, anxiety-related behavior as an index of impulsivity was significantly increased in SHRSP. In the Y-maze task, spontaneous alternation behavior as an index of attention was significantly lowered in male, but not in female SHRSP, indicating gender specificity. Methylphenidate significantly attenuated locomotor hyperactivity at low doses, and dosedependently improved the spontaneous alternation deficit in SHRSP. On the basis of these behavioral and pharmacological features, we have presented here that juvenile SHRSP are an appropriate animal model of AD/HD, for providing insights into the pathogenesis and developing therapeutic strategies.
