Free-running of plasma melatonin rhythm prior to full manifestation of a non-24 hour sleep-wake syndrome.
A long-term observation of a sighted man who developed a non-24 h sleep-wake syndrome is reported. A partial entrainment was observed first, whereby the sleep-wake rhythm was entrained by the day-night alternation whereas the circadian rhythm in plasma melatonin was free-running. Two years later, the sleep-wake rhythm of this subject started to free-run together with the melatonin rhythm. Oral administration of melatonin for 2 weeks improved the entrainability of both rhythms but failed to entrain the rhythms completely. It is concluded that the free-running of the circadian pacemaker preceded a full manifestation of a non-24 h sleep-wake syndrome in this particular subject.
Hashimoto
S
S
Department of Physiology, Hokkaido University School of Medicine, Sapporo, Japan.
Nakamura
K
K
Honma
S
S
Honma
K
K
D000284:Administration, Oral; D000328:Adult; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000097:blood*; D017286:Polysomnography; D011603:Psychophysiology; D012893:Sleep Wake Disorders / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D013577:Syndrome
D008550:Melatonin