title: Modulation of ion channels in rod photoreceptors by nitric oxide.
abstract: 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.
authors.affiliation: Neuroscience Research Group University of Calgary, Alberta, Canada.
authors.forename: D E
authors.initials: DE
authors.lastname: Kurenny
authors.forename: L L
authors.initials: LL
authors.lastname: Moroz
authors.forename: R W
authors.initials: RW
authors.lastname: Turner
authors.forename: K A
authors.initials: KA
authors.lastname: Sharkey
authors.forename: S
authors.initials: S
authors.lastname: Barnes
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D006152:Cyclic GMP / Q000502:physiology; D003545:Cysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D004110:Diltiazem / Q000494:pharmacology; D015640:Ion Channel Gating; D008274:Magnesium / Q000494:pharmacology; D009252:NADPH Dehydrogenase / Q000378:metabolism; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D026403:S-Nitrosothiols; D014562:Caudata
chemical_list: D015220:Calcium Channels; D026403:S-Nitrosothiols; D009569:Nitric Oxide; C021315:S-nitrosocysteine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D009252:NADPH Dehydrogenase; D004110:Diltiazem; D006152:Cyclic GMP; D008274:Magnesium; D003545:Cysteine