title: Association of BDNF Val66Met polymorphism with HPA and SAM axis reactivity to psychological and physical stress.
abstract: BACKGROUND
  Decreased expression of brain-derived neurotrophic factor (BDNF) is implicated in enhanced stress responses. The BDNF Val66Met polymorphism is associated with psychological changes; for example, carriers of the Met allele exhibit increased harm avoidance as well as a higher prevalence of depression and anxiety disorder.
  
  
  METHODS
  To analyze the effects of BDNF Val66Met on stress responses, we tested 226 university students (88 women and 138 men) using a social stress procedure (Trier Social Stress Test [TSST]) and an electrical stimulation stress test. Stress indices were derived from repeated measurements of salivary α-amylase, salivary cortisol, heart rate, and psychological testing during the stress tests. All subjects were genotyped for the Val66Met polymorphism (G196A).
  
  
  RESULTS
  A significant three-way interaction (time [3 levels] × BDNF [Val/Val, Val/Met, Met/Met]; P<0.05) was demonstrated that revealed different salivary cortisol responses in the TSST but not in electrical stimulation. Met/Met women had stronger cortisol responses than Val/Met and Val/Val individuals in the TSST. Met/Met men exhibited stronger salivary cortisol responses than Val/Met and Val/Val individuals in the TSST.
  
  
  CONCLUSIONS
  These results indicate that a common, functionally significant polymorphism in BDNF had different effects on hypothalamic-pituitary-adrenocortical axis reactivity but not on sympathetic adrenomedullary reactivity in TSST and electrical stimulation tests.
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Jusen
authors.initials: J
authors.lastname: Tsuru
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ishitobi
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Maruyama
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Inoue
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Aimi
authors.initials: A
authors.lastname: Kawano
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Ikeda
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ando
authors.affiliation: Department of Applied Linguistics, Faculty of Medicine, Oita University, Oita, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Oshita
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Saeko
authors.initials: S
authors.lastname: Aizawa
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Masuda
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Higuma
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kanehisa
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Taiga
authors.initials: T
authors.lastname: Ninomiya
authors.affiliation: Department of Neuropsychiatry, Oita University, Oita, Japan.
authors.forename: Jotaro
authors.initials: J
authors.lastname: Akiyoshi
keywords: brain-derived neurotrophic factor; cortisol; saliva; stress