CSF neurochemicals during tryptophan depletion in individuals with remitted depression and healthy controls

Francisco A. Moreno, Damian Parkinson, Craig Palmer, Wm Lesley Castro, John Misiaszek, Aram El Khoury, Aleksander A. Mathé, Ron Wright, Pedro L. Delgado

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


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 (ΣLNAA) (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 ΣLNAA 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 ΣLNAA when using the TRP depletion paradigm. The use of a single CSF sampling technique although practical may result in data acquisition limitations.

Original languageEnglish (US)
Pages (from-to)18-24
Number of pages7
JournalEuropean Neuropsychopharmacology
Issue number1
StatePublished - Jan 2010


  • Cerebrospinal fluid (CSF)
  • Monoamine metabolites
  • Neuropeptide Y
  • Sum of large neutral amino acids (ΣLNAA)
  • Tryptophan depletion

ASJC Scopus subject areas

  • Pharmacology
  • Neurology
  • Clinical Neurology
  • Psychiatry and Mental health
  • Biological Psychiatry
  • Pharmacology (medical)


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