Abstract
Tryptophan (TRP) depletion was used to study serotonin because the ratio of TRP to large neutral amino acids (TRP/LNAA) determines the quantity of TRP that enters the brain. Because TRP is not universally available, a modified technique of TRP depletion was developed where a 1/4 strength preparation of an amino acid mixture (AAM) replaces TRP as the placebo. Seven healthy subjects could not differentiate between the preparations in this double-blind, placebo-controlled study. Urinary 6-hydroxymelatonin sulfate (6-MS) was monitored as a biochemical marker of serotonin. The TRP/LNAA ratio (GG = 0.0001) and 6-MS secretion (GG = 0.024) were decreased, but placebo TRP levels (GG = 0.062) were not altered significantly. This modified technique facilitates the sue of TRP depletion in clinical research.
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Krahn, L., Lu, P., Klee, G. et al. Examining Serotonin Function: A Modified Technique for Rapid Tryptophan Depletion. Neuropsychopharmacol 15, 325–328 (1996). https://doi.org/10.1016/0893-133X(95)00273-G
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DOI: https://doi.org/10.1016/0893-133X(95)00273-G
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