title: Effect of atomoxetine on hyperactivity in an animal model of attention-deficit/hyperactivity disorder (ADHD).
abstract: BACKGROUND
  Hyperactivity related behaviors as well as inattention and impulsivity are regarded as the nuclear symptoms of attention-deficit/hyperactivity disorder (ADHD).
  
  
  OBJECTIVE
  To investigate the therapeutic effects of atomoxetine on the motor activity in relation to the expression of the dopamine (DA) D2 receptor based on the hypothesis that DA system hypofunction causes ADHD symptoms, which would correlate with extensive D2 receptor overproduction and a lack of DA synthesis in specific brain regions: prefrontal cortex (PFC), striatum, and hypothalamus.
  
  
  METHODS
  Young male spontaneously hypertensive rats (SHR), animal models of ADHD, were randomly divided into four groups according to the daily dosage of atomoxetine and treated for 21 consecutive days. The animals were assessed using an open-field test, and the DA D2 receptor expression was examined.
  
  
  RESULTS
  The motor activity improved continuously in the group treated with atomoxetine at a dose of 1 mg/Kg/day than in the groups treated with atomoxetine at a dose of 0.25 mg/Kg/day or 0.5 mg/Kg/day. With respect to DA D2 receptor immunohistochemistry, we observed significantly increased DA D2 receptor expression in the PFC, striatum, and hypothalamus of the SHRs as compared to the WKY rats. Treatment with atomoxetine significantly decreased DA D2 expression in the PFC, striatum, and hypothalamus of the SHRs, in a dose-dependent manner.
  
  
  CONCLUSIONS
  Hyperactivity in young SHRs can be improved by treatment with atomoxetine via the DA D2 pathway.
authors.affiliation: Department of Psychiatry, Daedong Hospital, Daegu, Korea.
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Moon
authors.affiliation: Department of Physiology, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Chang Ju
authors.initials: CJ
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Yeon Jung
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, Dankook University Medical College, Cheonan, Korea.
authors.forename: Minha
authors.initials: M
authors.lastname: Hong
authors.affiliation: Department of Psychiatry, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Juhee
authors.initials: J
authors.lastname: Han
authors.affiliation: Department of Psychiatry, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Geon Ho
authors.initials: GH
authors.lastname: Bahn
mesh_terms: D018759:Adrenergic Uptake Inhibitors / Q000627:therapeutic use*; D000818:Animals; D000069445:Atomoxetine Hydrochloride / Q000627:therapeutic use*; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D018759:Adrenergic Uptake Inhibitors; D000069445:Atomoxetine Hydrochloride