title: Differences in salivary alpha-amylase and cortisol responsiveness following exposure to electrical stimulation versus the Trier Social Stress Tests.
abstract: BACKGROUND
  Cortisol is an essential hormone in the regulation of the stress response along the HPA axis, and salivary cortisol has been used as a measure of free circulating cortisol levels. Recently, salivary alpha-amylase (sAA) has also emerged as a novel biomarker for psychosocial stress responsiveness within the sympathetic adrenomedullary (SAM) system.
  
  
  RESULTS
  We measured sAA and salivary cortisol in healthy volunteers after exposure to the Trier Social Stress Test (TSST) and electric stimulation stress. One hundred forty-nine healthy volunteers participated in this study. All subjects were exposed to both the TSST and electric stimulation stress on separate days. We measured sAA and salivary cortisol levels three times immediately before, immediately after, and 20 min after the stress challenge. The State (STAI-S) and Trait (STAI-T) versions of the Spielberger Anxiety Inventory test and the Profile of Mood State (POMS) tests were administered to participants before the electrical stimulation and TSST protocols. We also measured HF, LF and LF/HF Heart Rate Variability ratio immediately after electrical stimulation and TSST exposure. Following TSST exposure or electrical stimulation, sAA levels displayed a rapid increase and recovery, returning to baseline levels 20 min after the stress challenge. Salivary cortisol responses showed a delayed increase, which remained significantly elevated from baseline levels 20 min after the stress challenge. Analyses revealed no differences between men and women with regard to their sAA response to the challenges (TSST or electric stimulations), while we found significantly higher salivary cortisol responses to the TSST in females. We also found that younger subjects tended to display higher sAA activity. Salivary cortisol levels were significantly correlated with the strength of the applied electrical stimulation.
  
  
  CONCLUSIONS
  These preliminary results suggest that the HPA axis (but not the SAM system) may show differential response patterns to distinct kinds of stressors.
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Yufu-Shi, Oita, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Maruyama
authors.forename: Aimi
authors.initials: A
authors.lastname: Kawano
authors.forename: Shizuko
authors.initials: S
authors.lastname: Okamoto
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ando
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ishitobi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Ayako
authors.initials: A
authors.lastname: Inoue
authors.forename: Junko
authors.initials: J
authors.lastname: Imanaga
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kanehisa
authors.forename: Haruka
authors.initials: H
authors.lastname: Higuma
authors.forename: Taiga
authors.initials: T
authors.lastname: Ninomiya
authors.forename: Jusen
authors.initials: J
authors.lastname: Tsuru
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hanada
authors.forename: Jotaro
authors.initials: J
authors.lastname: Akiyoshi
mesh_terms: D000328:Adult; D001007:Anxiety / Q000201:enzymology / Q000378:metabolism; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012463:Saliva / Q000201:enzymology* / Q000378:metabolism; D012737:Sex Factors; D018709:Statistics, Nonparametric; D013315:Stress, Psychological / Q000201:enzymology* / Q000378:metabolism; D011795:Surveys and Questionnaires; D055815:Young Adult; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D000516:alpha-Amylases; D006854:Hydrocortisone