No evidence for extraocular photoreceptors in the circadian system of the Syrian hamster

Shin Yamazaki, Maki Goto, Michael Menaker

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

Campbell and Murphy reported recently that 3 h of bright light (13,000 lux) exposure to the area behind the knee caused phase shifts of the circadian rhythms of both body temperature and saliva melatonin in humans. The authors tested the hypothesis that extraocular photoreception is also involved in the circadian system of the Syrian hamster. Hamsters were bilaterally enucleated (eyes removed), and their backs were shaved. Hamsters with stable free-running rhythms in constant darkness were exposed to direct sunlight for 1 or 3 hours during their subjective night. Intact (control) animals showed phase shifts as expected, but the locomotor activity of enucleated animals was unaffected by the exposure to sunlight. The authors also measured the pineal melatonin content after exposure to sunlight. Pineal melatonin content in intact animals declined markedly as expected, but no decline was observed in the enucleated hamsters. The authors conclude that extraocular phototransduction is not capable of shifting the phase of the hamster's locomotor activity rhythm or of suppressing pineal melatonin synthesis.

Original languageEnglish (US)
Pages (from-to)197-201
Number of pages5
JournalJournal of Biological Rhythms
Volume14
Issue number3
StatePublished - Jun 1999

Fingerprint

Mesocricetus
melatonin
Melatonin
photoreceptors
hamsters
Cricetinae
Sunlight
solar radiation
Locomotion
locomotion
Light Signal Transduction
phototransduction
animals
Darkness
knees
back (body region)
Circadian Rhythm
saliva
Body Temperature
Saliva

Keywords

  • Circadian photoreceptor
  • Circadian rhythm
  • Extraocular photoreceptor
  • Jet lag
  • Melatonin
  • Pineal
  • Syrian hamster

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Physiology
  • Physiology (medical)

Cite this

No evidence for extraocular photoreceptors in the circadian system of the Syrian hamster. / Yamazaki, Shin; Goto, Maki; Menaker, Michael.

In: Journal of Biological Rhythms, Vol. 14, No. 3, 06.1999, p. 197-201.

Research output: Contribution to journalArticle

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