Endogenous nitric oxide enhances the light-response of cones during light-adaptation in the rat retina.
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.
Biology Research Division, Graduate School of Science, Toho University, 2-2-1 Miyama, Funabashi, 274-8510 Chiba, Japan.
Masaki
M
Sato
Teruya
T
Ohtsuka
William K
WK
Stell
D000221:Adaptation, Ocular / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D004596:Electroretinography / Q000187:drug effects; D008027:Light; D009569:Nitric Oxide / Q000494:pharmacology / Q000502:physiology*; D010775:Photic Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000502:physiology; D017949:Retinal Cone Photoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D012970:Sodium Glutamate / Q000494:pharmacology; D013012:Sorbitol / Q000031:analogs & derivatives
C404528:nitric oxide scavenger 100; D009569:Nitric Oxide; D013012:Sorbitol; D012970:Sodium Glutamate