Effects of a tryptophan-free amino acid drink challenge on normal human sleep electroencephalogram and mood.
BACKGROUND
Serotonin has been implicated in the regulation of sleep and mood. In animals a tryptophan-free amino acid drink (TFD) challenge has been found to reduce brain serotonin. We hypothesized this TFD would produce alterations in electroencephalographic (EEG) sleep commonly associated with depression, i.e. an enhancement of rapid eye movement (REM) sleep, and adversely affect mood ratings in humans.


METHODS
We investigated the effects of a TFD challenge in 11 healthy male subjects on EEG sleep and mood (assessed by Profile of Mood States). All subjects received on separate occasions an experimental drink containing approximately 100 g of an amino acid mixture (100% TFD) and a control drink containing one fourth strength (25% TFD) of the experimental drink 5 hours prior to sleep (6:00 PM).


RESULTS
Both drinks significantly decreased plasma tryptophan levels 5 hours postchallenge (11:00 PM). Both drinks significantly decreased REM latency, and the 25% TFD also increased REM time and REM% compared to baseline. No significant changes were found in subjective ratings of depression; however, subjects reported confusion and tension and a decrease in elation, vigor, and friendliness compared with baseline.


CONCLUSIONS
These TFD findings further support the involvement of serotonin deficiency in EEG sleep findings commonly seen in depression.
Bhatti
T
T
Department of Psychiatry, University of California at San Diego 92161, USA.
Gillin
J C
JC
Seifritz
E
E
Moore
P
P
Clark
C
C
Golshan
S
S
Stahl
S
S
Rapaport
M
M
Kelsoe
J
J
D000328:Adult; D000339:Affect / Q000187:drug effects*; D000596:Amino Acids / Q000009:adverse effects / Q000494:pharmacology*; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000187:drug effects; D012701:Serotonin / Q000378:metabolism / Q000502:physiology; D012890:Sleep / Q000187:drug effects*; D012895:Sleep, REM / Q000187:drug effects; D014364:Tryptophan / Q000097:blood / Q000502:physiology*
D000596:Amino Acids; D012701:Serotonin; D014364:Tryptophan