Human melatonin suppression by light: a case for scotopic efficiency.
Human adult males were exposed to combinations of two illuminances and two spectral power distributions over the course of four nighttime sessions. A dose-dependent response of acute melatonin suppression to light was found, but photopic (cone-based) illuminance did not adequately predict suppression. When melatonin suppression was plotted against scotopic (rod-based) illuminance, the data formed a nearly monotonic function, implicating rods, or a rod-dominated mechanism, in the human melatonin regulation system. The results do not, however, rule out mechanisms other than rods, including novel photoreceptors, as candidates for melatonin regulation in humans.
Rea
M S
MS
Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12180, USA. ream@rpi.edu
Bullough
J D
JD
Figueiro
M G
MG
D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D003623:Dark Adaptation / Q000502:physiology; D003624:Darkness; D006801:Humans; D008027:Light; D055537:Light Signal Transduction / Q000502:physiology*; D008297:Male; D008550:Melatonin / Q000097:blood / Q000378:metabolism*; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods; D010870:Pineal Gland / Q000378:metabolism; D011863:Radioimmunoassay; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*
D008550:Melatonin