Our hosting provider will be performing UPS maintenance on Tuesday, Oct 25, 2016 between 8 AM and 5 PM PDT. SciCrunch searching services will be down during this time.

Preparing your results

Our searching services are busy right now. Your search will reload in five seconds.

Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Melanopsin (Opn4) requirement for normal light-induced circadian phase shifting.


The master circadian oscillator in the hypothalamic suprachiasmatic nucleus is entrained to the day/night cycle by retinal photoreceptors. Melanopsin (Opn4), an opsin-based photopigment, is a primary candidate for photoreceptor-mediated entrainment. To investigate the functional role of melanopsin in light resetting of the oscillator, we generated melanopsin-null mice (Opn4-/-). These mice entrain to a light/dark cycle and do not exhibit any overt defect in circadian activity rhythms under constant darkness. However, they display severely attenuated phase resetting in response to brief pulses of monochromatic light, highlighting the critical role of melanopsin in circadian photoentrainment in mammals.

Pubmed ID: 12481141


  • Panda S
  • Sato TK
  • Castrucci AM
  • Rollag MD
  • DeGrip WJ
  • Hogenesch JB
  • Provencio I
  • Kay SA


Science (New York, N.Y.)

Publication Data

December 13, 2002

Associated Grants

  • Agency: NIMH NIH HHS, Id: MH 62405
  • Agency: NIMH NIH HHS, Id: MH51573

Mesh Terms

  • Animals
  • Biological Clocks
  • Circadian Rhythm
  • Darkness
  • Female
  • Gene Targeting
  • Light
  • Light Signal Transduction
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Motor Activity
  • Retinal Ganglion Cells
  • Rod Opsins
  • Suprachiasmatic Nucleus