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Tryptophan and Sleep in Young Adults
Author(s) -
Griffiths William J.,
Lester Boyd K.,
Coulter Joe D.,
Williams Harold L.
Publication year - 1972
Publication title -
psychophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.661
H-Index - 156
eISSN - 1469-8986
pISSN - 0048-5772
DOI - 10.1111/j.1469-8986.1972.tb03218.x
Subject(s) - serotonin , sleep (system call) , tryptophan , psychology , slow wave sleep , rapid eye movement sleep , electroencephalography , sleep stages , sleep onset , sedative , circadian rhythm , endocrinology , medicine , insomnia , neuroscience , polysomnography , psychiatry , chemistry , biochemistry , receptor , amino acid , computer science , operating system
Oral administration of L‐tryptophan increases brain serotonin levels by following normal 5‐hydroxyindole pathways (Moir & Eccleston, 1968). Since recent studies (Jouvet, 1969) suggest that serotonin is important in controlling sleep mechanisms, L‐tryptophan provides a useful method for investigating further the role of serotonin in sleep. In two experiments, EEG sleep patterns from 21 young adult males were examined following moderate (7.5 g) and high (12 g) oral doses of L‐tryptophan. Moderate doses produced sedative effects (reports of extreme drowsiness and reduced time awake) accompanied by increased slow‐wave sleep. The only effects on REM parameters were a trend (in some Ss) to early onset of stage REM, a small decrease in the period of the REM cycle, and decreased density of rapid eye movements. With the high dose, Ss again reported extreme drowsiness, and time to sleep onset was decreased. However, changes in SW sleep and waking time appeared only as non‐significant trends. In the high‐dose group, percent of REM sleep was markedly increased, due to early onset of stage REM and to increased duration of REM episodes during the second half of the night. EEG sleep patterns on recovery nights following large doses of tryptophan were not systematically different from baseline nights. These results indicate that the changes in sleep patterns produced by L‐tryptophan, presumably acting through 5‐hydroxyindole pathways, are dependent on dose. The findings are consistent with the idea that serotonin, or one of its metabolites, is involved in the mechanisms controlling both SW and REM sleep.