title: Intra- and inter-individual relationships between central and peripheral serotonergic activity in humans: a serial cerebrospinal fluid sampling study.
abstract: Data are lacking concerning the longitudinal covariability and cross-sectional balance between central and peripheral 5-HIAA concentrations in humans and on the possible associations between tobacco smoking or post-traumatic stress disorder (PTSD) and CSF and plasma 5-HIAA concentrations. Using serial cerebrospinal fluid (CSF) and blood sampling, we determined the concentrations of 5-HIAA in CSF and plasma over 6 h, and examined their relationships in healthy volunteers and patients with PTSD-both smokers and nonsmokers. Patients with PTSD and healthy volunteers had very similar CSF 5-HIAA concentrations. Significant and positive correlations between CSF and plasma 5-HIAA levels were observed within individuals, but this CNS-peripheral 5-HIAA relationship was significantly reduced in smokers (nonsmokers: mean r = 0.559 +/- 0.072; smokers: mean r = 0.329 +/- 0.064 p < 0.038). No significant cross-sectional, interindividual correlation of mean CSF and mean plasma 5-HIAA was seen (r = 0.094). These data show that changes in CSF 5-HIAA levels within an individual over time are largely reflected in plasma 5-HIAA, albeit significantly less so in smokers. The present results therefore suggest that clinically, longitudinal determination of plasma 5-HIAA concentrations within an individual patient can be used to make inferences about relative changes in integrated CSF 5-HIAA concentrations. However, plasma 5-HIAA concentrations provide no significant information about absolute levels of the serotonin metabolite in the CSF.
authors.affiliation: Department of Psychiatry, Cincinnati VAMC and University of Cincinnati College of Medicine, Cincinnati, OH, USA. strwanjr@ucmail.uc.edu
authors.forename: J R
authors.initials: JR
authors.lastname: Strawn
authors.forename: N N
authors.initials: NN
authors.lastname: Ekhator
authors.forename: R M
authors.initials: RM
authors.lastname: Anthenelli
authors.forename: D G
authors.initials: DG
authors.lastname: Baker
authors.forename: R A
authors.initials: RA
authors.lastname: Maxwell
authors.forename: K K
authors.initials: KK
authors.lastname: Hill
authors.forename: T D
authors.initials: TD
authors.lastname: Geracioti
mesh_terms: D000328:Adult; D002490:Central Nervous System / Q000502:physiology*; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid; D008297:Male; D017933:Peripheral Nervous System / Q000502:physiology*; D012701:Serotonin / Q000134:cerebrospinal fluid*; D012907:Smoking / Q000134:cerebrospinal fluid; D013313:Stress Disorders, Post-Traumatic / Q000134:cerebrospinal fluid
chemical_list: D012701:Serotonin; D006897:Hydroxyindoleacetic Acid