The influence of intravenous L-tryptophan on plasma melatonin and sleep in men.
The sleep-inducing mechanisms of L-Tryptophan (L-Trp) are generally thought to be mediated by a central serotonergic activation. Evidence is presented that some effects of L-Trp on sleep may be mediated by melatonin, a Trp-metabolite with sedative properties. Trp effects on vigilance, sleep, and plasma-melatonin concentrations were measured after double-blind application of 0, 1, 3, and 5 g L-Trp in nine and five healthy probands during daytime and nighttime, respectively. A significant sleep-inducing effect was observed after L-Trp administration during daytime and nighttime. The infusions of L-Trp caused a massive elevation of plasma melatonin levels. This effect was significant both during the night and the day, indicating that the increment of circulating melatonin may be of extrapineal origin.
Hajak
G
G
Department of Psychiatry, University of Göttingen, Germany.
Huether
G
G
Blanke
J
J
Blömer
M
M
Freyer
C
C
Poeggeler
B
B
Reimer
A
A
Rodenbeck
A
A
Schulz-Varszegi
M
M
Rüther
E
E
D000328:Adult; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008550:Melatonin / Q000097:blood*; D011863:Radioimmunoassay; D012890:Sleep / Q000187:drug effects*; D014364:Tryptophan / Q000008:administration & dosage / Q000494:pharmacology*
D014364:Tryptophan; D008550:Melatonin