Plasma L-Tryptophan Levels, Subjective Sleepiness and Daytime Sleep

摘要

The amino acid, 1-tryptophan, is the direct dietary precursor of brain serotonin. The inconsistent effects of 1-tryptophan on nighttime sleep are reviewed. Effects on daytime nap sleep are presented. L-tryptophan (4 grams) significantly reduces daytime sleep latency in morning and afternoon naps, without alteration of sleep stages. The waking EEG shows significantly more alpha and theta following 1-tryptophan administration. These findings are consistent with other daytime studies showing significant elevations in subjective sleepings on the Standford Sleepiness Scale following 1-tryptophan. L-tryptophan is described as a mild and physiological hypnotic which is effective when administered in environments conducive to sleep. (Author)