Examining serotonin function: A modified technique for rapid tryptophan depletion

Lois E. Krahn; Peter Y. Lu; George Klee; Pedro R. Delgado; Slong Chi Lin; Ralf C. Zimmermann

doi:10.1016/0893-133X(95)00273-G

Examining serotonin function: A modified technique for rapid tryptophan depletion

Lois E. Krahn, Peter Y. Lu, George Klee, Pedro R. Delgado, Slong Chi Lin, Ralf C. Zimmermann

Research output: Contribution to journal › Review article › peer-review

32 Scopus citations

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 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 use of TRP depletion in clinical research.

Original language	English (US)
Pages (from-to)	325-328
Number of pages	4
Journal	Neuropsychopharmacology
Volume	15
Issue number	4
DOIs	https://doi.org/10.1016/0893-133X(95)00273-G
State	Published - Oct 1996

Keywords

Competing amino acids
Melatonin
Mood
Serotonin
Tryptophan

ASJC Scopus subject areas

Pharmacology
Psychiatry and Mental health

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10.1016/0893-133X(95)00273-G

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title = "Examining serotonin function: A modified technique for rapid tryptophan depletion",

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 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 use of TRP depletion in clinical research.",

keywords = "Competing amino acids, Melatonin, Mood, Serotonin, Tryptophan",

author = "Krahn, {Lois E.} and Lu, {Peter Y.} and George Klee and Delgado, {Pedro R.} and Lin, {Slong Chi} and Zimmermann, {Ralf C.}",

note = "Funding Information: This project was supported by a NARSAD Young Investigator Award to RCZ and the General Clinical Research Center (GCRC), Mayo Foundation (grant # M01 RR585). The authors wish to thank the nursing staff of the GCRC, particularly study coordinator Jean Feehan-Hofbauer, R.N. We also appreciate the work of Ms. Darlene Lucas (6-MS assays) and James D. Jones, Ph.D. (amino acids analysis).",

year = "1996",

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doi = "10.1016/0893-133X(95)00273-G",

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T1 - Examining serotonin function

T2 - A modified technique for rapid tryptophan depletion

AU - Krahn, Lois E.

AU - Lu, Peter Y.

AU - Klee, George

AU - Delgado, Pedro R.

AU - Lin, Slong Chi

AU - Zimmermann, Ralf C.

N1 - Funding Information: This project was supported by a NARSAD Young Investigator Award to RCZ and the General Clinical Research Center (GCRC), Mayo Foundation (grant # M01 RR585). The authors wish to thank the nursing staff of the GCRC, particularly study coordinator Jean Feehan-Hofbauer, R.N. We also appreciate the work of Ms. Darlene Lucas (6-MS assays) and James D. Jones, Ph.D. (amino acids analysis).

PY - 1996/10

Y1 - 1996/10

N2 - 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 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 use of TRP depletion in clinical research.

AB - 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 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 use of TRP depletion in clinical research.

KW - Competing amino acids

KW - Melatonin

KW - Mood

KW - Serotonin

KW - Tryptophan

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Examining serotonin function: A modified technique for rapid tryptophan depletion

Abstract

Keywords

ASJC Scopus subject areas

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