Influence of endotoxin on daytime sleep in humans.
Administration of endotoxin in the evening has been shown to transiently suppress rapid eye movement (REM) and to promote non-REM sleep in humans. In a single-blind placebo-controlled crossover design, we assessed the effects of Salmonella abortus equi endotoxin administered intravenously in the morning on the primary host response and on daytime sleep by use of a multiple napping protocol in healthy volunteers. The extent of the host response achieved by 0.8 ng of endotoxin per kg of body weight given at 0900 h was comparable to that previously reported to result from the administration of 0.4 ng/kg at 1900 h. However, sleep was only slightly influenced. Endotoxin reduced the amount of REM sleep and increased REM latency. Non-REM sleep amount in the first nap, although not significantly changed, correlated negatively with the individual peak levels of interleukin-6 (r = -0.73, P < 0.05). Subjective tiredness, sleep onset latency, total sleep time, and the amounts of slow-wave and non-REM sleep were not affected by endotoxin throughout the entire experiment. Spectral analysis of the electroencephalogram obtained during non-REM sleep yielded no condition differences. We conclude that endotoxin administration in the morning to healthy volunteers, while activating the host defense to the same extent as a lower dose that has been reported to promote non-REM sleep when given in the evening, does not affect non-REM sleep. REM sleep suppression is, to date, the most consistently reported effect of endotoxin on human sleep.
Korth
C
C
Clinical Institute, Max Planck Institute of Psychiatry, Munich, Germany.
Mullington
J
J
Schreiber
W
W
Pollmächer
T
T
D000328:Adult; D018592:Cross-Over Studies; D004731:Endotoxins / Q000633:toxicity*; D006801:Humans; D008297:Male; D016037:Single-Blind Method; D012890:Sleep / Q000187:drug effects*; D012895:Sleep, REM / Q000187:drug effects
D004731:Endotoxins