title: [123I] ADAM brainstem binding correlates with the loudness dependence of auditory evoked potentials.
abstract: The in vivo assessment of brain serotonergic function might be of clinical relevance in neuropsychiatry. The loudness dependence of auditory evoked potentials (LD) has been proposed as an indirect indicator of cortical serotonergic activity, whereas single photon emission computed tomography (SPECT) and [123I]ADAM allow the selective assessment of brain serotonin transporters (SERT). The aim of this study was to investigate LD and SERT availability as independent variables of the brain serotonergic system in healthy volunteers. Fifteen (six male, nine female) subjects received both neurophysiological and imaging investigations. Evoked potentials were recorded following the application of acoustic stimuli with increasing intensities; the LD was analyzed using dipole source analysis. SPECT was performed four hours after injection of 137 +/- 11.4 MBq [123I]ADAM. As a measure of SERT availability specific ADAM brainstem binding was used. LD correlated significantly with SERT availability (Pearson's correlations: rho = -0.57, p < 0.05). The correlations remained significant after controlling for the effects of age or gender (partial correlations: rho = -0.60, p < 0.05) but were pronounced in the female group (rho = -0.83, p < 0.01). Associations between LD and SERT availability contribute to the understanding of the central serotonergic system and further validate the use of neurophysiological approaches as indirect measures of neurochemical brain activity.
authors.affiliation: Dept. of Psychiatry, Ludwig-Maximilians-University, Munich, Germany. oliver.pogarell@med.uni-muenchen.de
authors.forename: Oliver
authors.initials: O
authors.lastname: Pogarell
authors.forename: Walter
authors.initials: W
authors.lastname: Koch
authors.forename: Nadine
authors.initials: N
authors.lastname: Schaaff
authors.forename: Gabriele
authors.initials: G
authors.lastname: Pöpperl
authors.forename: Christoph
authors.initials: C
authors.lastname: Mulert
authors.forename: Georg
authors.initials: G
authors.lastname: Juckel
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Möller
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hegerl
authors.forename: Klaus
authors.initials: K
authors.lastname: Tatsch
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001933:Brain Stem / Q000000981:diagnostic imaging / Q000378:metabolism*; D002928:Cinanserin / Q000031:analogs & derivatives*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D019275:Radiopharmaceuticals; D012701:Serotonin / Q000378:metabolism / Q000502:physiology; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: C413491:2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine; D019275:Radiopharmaceuticals; D012701:Serotonin; D002928:Cinanserin