Modulation of ion channels in rod photoreceptors by nitric oxide

Neuron. 1994 Aug;13(2):315-24. doi: 10.1016/0896-6273(94)90349-2.


Subcellular compartments in the outer retina of the larval tiger salamander were identified as likely sites of production of nitric oxide (NO), a recently recognized intercellular messenger. NADPH diaphorase histochemistry and NO synthase immunocytochemistry labeled photoreceptor ellipsoids and the distal regions of bipolar and glial cells apposing photoreceptor inner segments, suggesting a role for NO in visual processing in the outer retina. We investigated the actions of NO on several rod photoreceptor ion channels. Application of the NO-generating compound S-nitrosocysteine increased Ca2+ channel current and a voltage-independent conductance, but had no affect on voltage-gated K+ or nonspecific cation currents. Given the steep relation between voltage-dependent Ca2+ influx and photoreceptor synaptic output, these results indicate that NO could modulate transmission of the photoresponse to second order cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Oxidoreductases / metabolism
  • Animals
  • Calcium Channels / drug effects
  • Calcium Channels / physiology*
  • Cyclic GMP / physiology
  • Cysteine / analogs & derivatives
  • Cysteine / pharmacology
  • Diltiazem / pharmacology
  • Ion Channel Gating*
  • Magnesium / pharmacology
  • NADPH Dehydrogenase / metabolism
  • Nitric Oxide / physiology*
  • Nitric Oxide Synthase
  • Retinal Rod Photoreceptor Cells / physiology*
  • S-Nitrosothiols*
  • Urodela


  • Calcium Channels
  • S-Nitrosothiols
  • Nitric Oxide
  • S-nitrosocysteine
  • Nitric Oxide Synthase
  • Amino Acid Oxidoreductases
  • NADPH Dehydrogenase
  • Diltiazem
  • Cyclic GMP
  • Magnesium
  • Cysteine