Functional absence of extraocular photoreception in hamster circadian rhythm entrainment.
The mammalian circadian pacemaker is entrainable by light via the retina. The putative role of extraocular light perception was investigated in blinded hamsters. These animals were shaved and exposed to a light-emitting pad for either 30 min or 3 h. The absence of any phase-shifting effects on wheel running activity rhythms indicates that extraocular light perception plays no functional role in photic entrainment of the circadian pacemaker in the hamster.
Department of Physiology, Leiden University Medical Centre, University of Leiden, P.O. Box 9604, 2300 RC, Leiden, Netherlands. j.h.meijer@physiology.medfac.leidenuniv.nl
J H
JH
Meijer
B
B
Thio
H
H
Albus
J
J
Schaap
A C
AC
Ruijs
D000818:Animals; D001766:Blindness / Q000503:physiopathology; D002940:Circadian Rhythm / Q000502:physiology*; D006224:Cricetinae; D010775:Photic Stimulation; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D012867:Skin / Q000528:radiation effects*; D014796:Visual Perception / Q000502:physiology*