A cGMP-gated cation channel and phototransduction in depolarizing photoreceptors of the lizard parietal eye

John T. Finn, Wei Hong Xiong, Eduardo C. Solessio, King Wai Yau

Research output: Contribution to journalArticle

Abstract

Photoreceptors of the lizard parietal eye, unlike rods and cones but like most invertebrate photoreceptors, respond to light under dark-adapted conditions with a depolarization. Using excised-patch recordings: we have nonetheless found a cGMP-gated, non-selective cation channel present at high density at the presumptive light-sensitive part (the outer segment) of these cells. This channel resembles the rod cGMP-gated channel in its activation characteristics, and by showing a relative non-selectivity among alkali monovalent cations, a high permeability to Ca2+, a high sensitivity to L-cis-diltiazem, as well as a negative modulation by Ca2+-calmodulin. This channel appears to mediate phototransduction by opening in the light to produce the depolarizing response.

Original languageEnglish (US)
Pages (from-to)1353-1357
Number of pages5
JournalVision Research
Volume38
Issue number10
DOIs
StatePublished - May 1 1998

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Keywords

  • Parietal eye
  • Photoreceptor
  • Phototransduction
  • cGMP
  • cGMP-gated channel

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

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