Nonvisual photoreception in the chick iris

Daniel C. Tu, Matthew L. Batten, Krzysztof Palczewski, Russell N. Van Gelder

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


The embryonic chicken iris constricts to light ex vivo, but with characteristics atypical of visual phototransduction. The chick iris was most sensitive to short-wavelength light, demonstrating an action spectrum consistent with cryptochrome rather than with opsin pigments. Pupillary responses did not attenuate after saturating light exposure, but showed paradoxical potentiation. Iris photosensitivity was not affected by retinoid depletion or inhibitors of visual phototransduction. Knockdown of cryptochrome expression, but not of melanopsin expression, decreased iris photosensitivity. These data characterize a non-opsin photoreception mechanism in a vertebrate eye and suggest a conserved photoreceptive role for cryptochromes in vertebrates.

Original languageEnglish (US)
Pages (from-to)129-131
Number of pages3
Issue number5693
StatePublished - Oct 1 2004
Externally publishedYes

ASJC Scopus subject areas

  • General


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