Maintenance of a circadian phase adjustment of the human melatonin rhythm following artificial long days.
In winter, a 5-day exposure of 4 human subjects to a skeleton photoperiod, with 3 h of bright light in the evening and again in the morning, phase advanced the morning serum melatonin offset by 1-3 h as compared with the original winter melatonin rhythm pattern. The phase advance persisted for 3 days even after the bright light withdrawal. The data indicate that the long skeleton photoperiod had a prevailing phase-advancing effect on the melatonin rhythm and its underlying pacemaker. The maintenance of the phase advance might be due to the fixed sleep-wake schedule.
Illnerová
H
H
Institute of Physiology, Academy of Sciences of Czech Republic, Prague.
Buresová
M
M
Nedvídková
J
J
Dvoráková
M
M
Zvolský
P
P
D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000097:blood; D017440:Photoperiod; D015398:Signal Transduction / Q000502:physiology*
D008550:Melatonin