title: Traumatic brain injury decreases serotonin transporter expression in the rat cerebrum.
abstract: OBJECTIVE
  An association has been postulated between traumatic brain injury (TBI) and depression. The serotonin transporter (SERT) regulates the concentration of serotonin in the synaptic cleft and represents a molecular target for antidepressants. We hypothesized that SERT expression in the brain changes following TBI.
  
  
  METHODS
  We performed immunohistochemistry, real-time polymerase chain reaction analysis for mRNA and western blot analysis for protein to examine the time-dependent changes in SERT expression in the cerebrum during the first 14 days after TBI, using a controlled cortical impact model in rats.
  
  
  RESULTS
  SERT immunoreactivity in neuronal fibres within the area adjacent to the cortical contusion decreased 1 to 14 days after injury. Significantly decreased SERT mRNA and protein expression were noted in the area adjacent to the cortical contusion 7 days after injury. There were no significant changes in SERT expression in the cingulum of the injured brain.
  
  
  CONCLUSIONS
  The findings of this study indicate that TBI decreases SERT expression in the cerebral cortex. The decreased levels of SERT expression after TBI may result in decreased serotonin neurotransmission in the brain and indicate a possible relationship with depression following TBI.
authors.affiliation: a Department of Neurosurgery , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Abe
authors.affiliation: b Department of Legal Medicine , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Shimada
authors.affiliation: a Department of Neurosurgery , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Okada
authors.affiliation: b Department of Legal Medicine , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kibayashi
mesh_terms: D000818:Animals; D000070642:Brain Injuries, Traumatic / Q000473:pathology*; D054022:Cerebrum / Q000378:metabolism*; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
chemical_list: D012333:RNA, Messenger; D050486:Serotonin Plasma Membrane Transport Proteins
keywords: Depression; SSRI; Serotonin transporter; Traumatic brain injury