Role of melanopsin in circadian responses to light

Norman F. Ruby, Thomas J. Brennan, Xinmin Xie, Vinh Cao, Paul Franken, H. Craig Heller, Bruce F. O'Hara

Research output: Contribution to journalArticlepeer-review

544 Scopus citations


Metanopsin 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.

Original languageEnglish
Pages (from-to)2211-2213
Number of pages3
Issue number5601
StatePublished - Dec 13 2002

ASJC Scopus subject areas

  • General


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