title: Is auditory evoked potential augmenting/reducing affected by acute tryptophan depletion?
abstract: Several lines of evidence suggest that the auditory evoked potential (AEP) augmenting/reducing slope may serve as a biological marker of central serotonergic activity. According to Hegerl and Juckel (Biol. Psychiatry, 33, 1993, 173), reduced serotonergic activity is hypothesized to increase the slope of the AEP amplitude stimulus intensity function (ASF-slope). Hints for this hypothesis were investigated by employing the acute tryptophan depletion paradigm in 18 healthy females. A within-subject, placebo controlled double-blind cross over design was used for that purpose. Subjects ingested both a 50 g amino-acid drink with (placebo condition) and without tryptophan (depletion condition). With respect to the N1/P2-slope, test-retest reliability of a 1 week interval ranged between r=0.56 and 0.58 for the pre-ingestion baseline recording sessions. Affect was not altered by tryptophan depletion and not related to the ASF-slope. The comparison between placebo and depletion conditions did not reveal significant alterations of the ASF-slope, neither after 5 nor 6 h post-ingestion. Thus, the results do not support the assumption of the ASF-slope reflecting central serotonergic function.
authors.affiliation: Department of Psychology II, Dresden University of Technology, Dresden, Germany. s.debener@fz-juelich.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Debener
authors.forename: Alexander
authors.initials: A
authors.lastname: Strobel
authors.forename: Katharina
authors.initials: K
authors.lastname: Kürschner
authors.forename: Cornelia
authors.initials: C
authors.lastname: Kranczioch
authors.forename: Jörg
authors.initials: J
authors.lastname: Hebenstreit
authors.forename: Andreas
authors.initials: A
authors.lastname: Maercker
authors.forename: André
authors.initials: A
authors.lastname: Beauducel
authors.forename: Burkhard
authors.initials: B
authors.lastname: Brocke
mesh_terms: D000328:Adult; D015415:Biomarkers; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D011237:Predictive Value of Tests; D012701:Serotonin / Q000502:physiology*; D014364:Tryptophan / Q000172:deficiency* / Q000502:physiology
chemical_list: D015415:Biomarkers; D012701:Serotonin; D014364:Tryptophan