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Oral Branched-Chain Amino Acid Supplements That Reduce Brain Serotonin During Exercise In Rats Also Lower Brain Catecholamines, Sujean Choi, Briana Disilvio, Madelyn H. Fernstrom, John D. Fernstrom

Biomedical Sciences Faculty Research and Publications

Exercise raises brain serotonin release and is postulated to cause fatigue in athletes; ingestion of branched-chain amino acids (BCAA), by competitively inhibiting tryptophan transport into brain, lowers brain tryptophan uptake and serotonin synthesis and release in rats, and reputedly in humans prevents exercise-induced increases in serotonin and fatigue. This latter effect in humans is disputed. But BCAA also competitively inhibit tyrosine uptake into brain, and thus catecholamine synthesis and release. Since increasing brain catecholamines enhances physical performance, BCAA ingestion could lower catecholamines, reduce performance and thus negate any serotonin-linked benefit. We therefore examined in rats whether BCAA would reduce both …