Role of melanopsin in circadian responses to light

Science. 2002 Dec 13;298(5601):2211-3. doi: 10.1126/science.1076701.

Abstract

Melanopsin has been proposed as an important photoreceptive molecule for the mammalian circadian system. Its importance in this role was tested in melanopsin knockout mice. These mice entrained to a light/dark cycle, phase-shifted after a light pulse, and increased circadian period when light intensity increased. Induction of the immediate-early gene c-fos was observed after a nighttime light pulse in both wild-type and knockout mice. However, the magnitude of these behavioral responses in knockout mice was 40% lower than in wild-type mice. Although melanopsin is not essential for the circadian clock to receive photic input, it contributes significantly to the magnitude of photic responses.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biological Clocks / physiology
  • Circadian Rhythm / physiology*
  • Darkness
  • Female
  • Gene Expression Regulation
  • Gene Targeting
  • Genes, fos
  • In Situ Hybridization
  • Light Signal Transduction
  • Light*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Motor Activity
  • Retinal Ganglion Cells / physiology
  • Rod Opsins / genetics
  • Rod Opsins / physiology*
  • Suprachiasmatic Nucleus / physiology

Substances

  • Rod Opsins
  • melanopsin