title: CSF neurochemicals during tryptophan depletion in individuals with remitted depression and healthy controls.
abstract: The purpose of this study was to examine the differential effects of acute tryptophan (TRP) depletion vs. sham condition on plasma, cerebrospinal fluid (CSF) biochemical parameters, and mood in the following three subject groups: (1) nine antidepressant-free individuals with remitted depression, (2) eight paroxetine-treated individuals with recently remitted depression, and (3) seven healthy controls. Plasma TRP decreased during TRP depletion and increased during sham condition (p<.01). CSF TRP and 5-hydroxyindoleacetic acid were lower during TRP depletion than sham condition (p<.01 each). During TRP depletion, CSF TRP correlated significantly with the plasma sum of large neutral amino acids (SigmaLNAA) (R=-.52, p=.01), but did not significantly correlate with plasma TRP (R=.15, p=.52). The correlation between CSF TRP and ratio of TRP to SigmaLNAA was R=.41 and p=.06 during TRP depletion, and R=-.44 and p=.04 during sham condition. A negative correlation trend was observed between CSF-TRP levels and peak Hamilton Depression Rating Scale scores during TRP depletion in patients recovered from depression (R=-.45, p=.07), but not in healthy controls (R=-.01, p=.98). CSF neuropeptide Y was higher during TRP depletion than sham condition (t=1.75, p<.10). These results illustrate the importance of assessing plasma SigmaLNAA when using the TRP depletion paradigm. The use of a single CSF sampling technique although practical may result in data acquisition limitations.
authors.affiliation: Department of Psychiatry, College of Medicine, The University of Arizona Health Sciences Center, 1501 N. Campbell Ave. 7-OPC, Tucson, AZ 85724, USA. fmoreno@u.arizona.edu
authors.forename: Francisco A
authors.initials: FA
authors.lastname: Moreno
authors.forename: Damian
authors.initials: D
authors.lastname: Parkinson
authors.forename: Craig
authors.initials: C
authors.lastname: Palmer
authors.forename: Wm Lesley
authors.initials: WL
authors.lastname: Castro
authors.forename: John
authors.initials: J
authors.lastname: Misiaszek
authors.forename: Aram
authors.initials: A
authors.lastname: El Khoury
authors.forename: Aleksander A
authors.initials: AA
authors.lastname: Mathé
authors.forename: Ron
authors.initials: R
authors.lastname: Wright
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Delgado
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002940:Circadian Rhythm / Q000187:drug effects; D018592:Cross-Over Studies; D003865:Major Depressive Disorder / Q000134:cerebrospinal fluid* / Q000188:drug therapy; D004311:Double-Blind Method; D004563:Electrochemistry / Q000379:methods; D005260:Female; D006719:Homovanillic Acid / Q000134:cerebrospinal fluid; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid; D007211:Indoles / Q000097:blood / Q000134:cerebrospinal fluid; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000134:cerebrospinal fluid; D008875:Middle Aged; D009448:Neurochemistry; D009478:Neuropeptide Y / Q000134:cerebrospinal fluid; D017374:Paroxetine / Q000494:pharmacology / Q000627:therapeutic use; D011569:Psychiatric Status Rating Scales; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D014364:Tryptophan / Q000097:blood / Q000134:cerebrospinal fluid / Q000172:deficiency*; D055815:Young Adult
chemical_list: D006719:Homovanillic Acid; D006897:Hydroxyindoleacetic Acid; D007211:Indoles; D008734:Methoxyhydroxyphenylglycol; D009478:Neuropeptide Y; D017374:Paroxetine; D017367:Selective Serotonin Reuptake Inhibitors; D014364:Tryptophan; C024139:indole-3-lactic acid