title: Decreased BDNF, trkB-TK+ and GAD67 mRNA expression in the hippocampus of individuals with schizophrenia and mood disorders.
abstract: BACKGROUND
  Brain-derived neurotrophic factor (BDNF), tyrosine kinase receptor (trkB-TK+) and glutamic acid decarboxylase (GAD67) mRNA levels have previously been found to be reduced in the prefrontal cortex of patients with schizophrenia. To determine whether this reduction extends to other brain regions, we measured the expression levels of BDNF, trkB-TK+ and GAD67 mRNA in regions of the hippocampus, including the dentate gyrus (DG), cornu ammonis subfields (CA1-4), subiculum and entorhinal cortex (EC) of individuals with schizophrenia, bipolar disorder, major depression and unaffected controls.
  
  
  METHODS
  In situ hybridization was performed on postmortem brain tissue obtained from the Stanley Foundation Consortium and analyzed using film-based quantification.
  
  
  RESULTS
  Analyses of covariance comparing the expression of mRNA among all groups revealed a significant decrease in BDNF mRNA in CA4 in the bipolar disorder group compared with controls (33%). We found trkB-TK+ mRNA levels to be significantly reduced in CA4 in the schizophrenia group (36%) and in layer II of the EC in the bipolar disorder and major depression groups (28%, 21%, respectively) compared with controls. In addition, GAD67 mRNA levels were reduced in patients with schizophrenia in both the DG (23%) and CA4 (60%) compared with controls. Individuals with major depression also expressed significantly less GAD67 mRNA (44%) compared with controls in CA4 of the hippocampus.
  
  
  CONCLUSIONS
  It is necessary to account for factors that influence the molecular preservation in postmortem brain tissue, including pH, postmortem interval and tissue storage time. Moreover, there are limitations to the sensitivity of the film-based method of quantification.
  
  
  CONCLUSIONS
  Our findings show abnormal BDNF, trkB-TK+ and GAD67 mRNA expression in the hippocampus of individuals with schizophrenia and mood disorders, indicating that fundamental properties of hippocampal signalling transmission, plasticity and circuitry may be affected in individuals with these major mental illnesses.
authors.affiliation: Stanley Laboratory of Brain Research, Rockville, MD 20850, USA. thompsonm@stanleyresearch.org
authors.forename: Mia
authors.initials: M
authors.lastname: Thompson Ray
authors.forename: Cynthia Shannon
authors.initials: CS
authors.lastname: Weickert
authors.forename: Eugene
authors.initials: E
authors.lastname: Wyatt
authors.forename: Maree J
authors.initials: MJ
authors.lastname: Webster
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020813:Receptor, trkB / Q000235:genetics / Q000378:metabolism*; D012559:Schizophrenia / Q000235:genetics / Q000378:metabolism*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D020813:Receptor, trkB; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1