Endogenous nitric oxide enhances the light-response of cones during light-adaptation in the rat retina

Vision Res. 2011 Jan;51(1):131-7. doi: 10.1016/j.visres.2010.10.011. Epub 2010 Oct 14.


The electroretinogram (ERG) is a non-invasive indicator of retinal function. Light flashes evoke a cornea-negative a-wave followed by a cornea-positive b-wave. Light-adaptation is known to increase the amplitude of cone-dependent b-waves. To identify the underlying mechanism, we recorded rat cone photoresponses in situ, using intravitreally-injected glutamate to block synaptic transmission and intense paired-flash stimuli to isolate cone a-waves. Steady adapting illumination caused a progressive increase in cone a-wave amplitude, which was suppressed in a dose-dependent manner by intravitreal CPTIO, a nitric oxide scavenger. We conclude that light-adaptation causes release of nitric oxide, which enhances the cone photoresponse.

MeSH terms

  • Adaptation, Ocular / drug effects
  • Adaptation, Ocular / physiology*
  • Animals
  • Electroretinography / drug effects
  • Light*
  • Nitric Oxide / pharmacology
  • Nitric Oxide / physiology*
  • Photic Stimulation
  • Rats
  • Rats, Sprague-Dawley
  • Retina / physiology
  • Retinal Cone Photoreceptor Cells / drug effects
  • Retinal Cone Photoreceptor Cells / physiology*
  • Sodium Glutamate / pharmacology
  • Sorbitol / analogs & derivatives


  • nitric oxide scavenger 100
  • Nitric Oxide
  • Sorbitol
  • Sodium Glutamate