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A new method for rapidly and simultaneously decreasing serotonin and catecholamine synthesis in humans
Marco Leyton1, Valerie Kwai Pun, Chawki Benkelfat
1Department of Psychiatry, McGill University, Montréal, Que. marco.leyton@mcgill.ca
Journal of Psychiatry & Neuroscience : JPN
|November 25, 2003
Summary
A novel amino acid mixture depleted of tryptophan, phenylalanine, and tyrosine effectively reduced precursor levels, impacting mood. This method shows promise for rapidly decreasing serotonin and catecholamine transmission.
Area of Science:
- Neuroscience
- Biochemistry
- Human Physiology
Background:
- Selective amino acid (AA) depletion can modulate neurotransmitter synthesis.
- Tryptophan deficiency reduces serotonin, while phenylalanine/tyrosine deficiency impacts catecholamines.
Purpose of the Study:
- To investigate the effect of a simultaneous tryptophan, phenylalanine, and tyrosine-deficient AA mixture on precursor levels.
- To assess if this depletion impacts protein synthesis and neurotransmitter precursor availability.
Main Methods:
- An open-label study involving ten healthy volunteers (5 male, 5 female).
- Administration of a specialized AA mixture lacking tryptophan, phenylalanine, and tyrosine.
- Measurement of plasma large neutral AA concentrations before and 5 hours post-ingestion.
Main Results:
- Significant reductions in plasma tryptophan, phenylalanine, and tyrosine levels (67-77%).
- Marked decreases in the ratio of these AAs to other large neutral AAs (87-90%).
- Reported mood alterations, including decreased elation, anxiety, confusion, and increased boredom/irritation.
Conclusions:
- Acute depletion of tryptophan, phenylalanine, and tyrosine is feasible.
- This depletion strategy may offer a novel method for simultaneously reducing serotonin and catecholamine transmission.
- The findings suggest a potential rapid intervention for modulating monoamine pathways.