title: Platelet uptake of GABA and glutamate in patients with bipolar disorder.
abstract: OBJECTIVE
  Gamma aminobutyric acid (GABA) and glutamate (Glu) are the major neurotransmitters of the human central nervous system, and their actions are determined by specific transporters. Several studies suggest that GABA- and Glu-uptake mechanisms are modified in patients with bipolar disorder (BD). We explored the functionality of the GABA and Glu transporters in three groups of patients with BD, each with a different polarity of index episode (manic, depressive, or euthymic) at the time of blood draw.
  
  
  METHODS
  Forty patients with a diagnosis of BD, according to DSM-IV-TR criteria, and 15 healthy subjects were enrolled in the study. GABA and Glu uptake were evaluated in freshly prepared platelets using [(3) H]GABA or [(3) H]glutamate.
  
  
  RESULTS
  Compared to controls, GABA uptake was significantly increased in patients with depressive episodes and significantly decreased in subjects with manic episodes. Glu uptake was significantly increased in patients with index manic episodes and in euthymic patients compared to healthy controls. Moreover, a positive correlation was found between GABA platelet uptake and Hamilton Depression Rating Scale scores and between Glu platelet uptake and Young Mania Rating Scale scores in patients with manic episodes.
  
  
  CONCLUSIONS
  We found a relationship between GABA- and Glu-uptake levels and the polarity of episodes in patients with BD. Our data suggest that the functionality of both GABA and Glu transporters could represent a useful neurobiological marker to characterize the real polarity of an index episode of illness in patients with BD.
authors.affiliation: Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology, University of Pisa, Pisa, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Daniele
authors.forename: Eleonora
authors.initials: E
authors.lastname: Da Pozzo
authors.forename: Marianna
authors.initials: M
authors.lastname: Abelli
authors.forename: Anna
authors.initials: A
authors.lastname: Panighini
authors.forename: Stefano
authors.initials: S
authors.lastname: Pini
authors.forename: Camilla
authors.initials: C
authors.lastname: Gesi
authors.forename: Lisa
authors.initials: L
authors.lastname: Lari
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cardini
authors.forename: Giovanni Battista
authors.initials: GB
authors.lastname: Cassano
authors.forename: Claudia
authors.initials: C
authors.lastname: Martini
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000097:blood*; D005260:Female; D018698:Glutamic Acid / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D012044:Regression Analysis; D014316:Tritium / Q000097:blood; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000097:blood*
chemical_list: D014316:Tritium; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid