Purchase this article with an account.
Ryan Tooker, Jozsef Vigh; Light driven S-nitrosylation in the retina. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4167.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Nitric oxide (NO) synthesis in the retina is triggered by light stimulation. NO has been shown to be a neuromodulator influencing light adaptation at various levels of visual signal processing, primarily by activation of the NO receptor soluble guanylate cyclase, consequent cGMP elevation and protein kinase G action. Recently, we reported that in goldfish retina endogenous or exogenous NO selectively enhanced Mb-type bipolar cell input/output ratio for dim scotopic inputs (≤2.4x108 photons/cm2/s) independent of cGMP and protein kinase G, and in fact, the NO effect was mediated through S-nitrosylation, in which NO covalently binds to the thiol group of a protein’s cysteine residue (Tooker et al, 2013). The purpose of this study was to examine light-evoked S-nitrosylation in the goldfish and mouse retina by immunohistochemical methods.
Standard immunohistochemical procedures were utilized for detection of S-nitrosylated proteins on 20 μm thick vertical sections of goldfish and mouse retinas. Retinas were exposed to various illumination protocols in order to produce distinct light adaptation states before paraformaldehyde fixation.
Dark adapted fish retinal sections were devoid of S-nitroso immunolabeling (SNI). In light adapted retinas, all retinal layers were strongly labeled, with particularly strong labeling in the inner plexiform (IPL) and ganglion cell layer (GCL). Goldfish retinas that received a light stimulation (1010 photons/cm2/s, 505 nm, 5-10 sec) capable of potentiating rod-mediated responses in Mb terminals (Tooker et al, 2013) showed relatively weak SNI in the ON sublamina of the IPL, often outlining Mb terminals. N-Ethylmaleimide, a potent inhibitor of S-nitrosylation reactions, eliminated SNI independent of illumination protocol. The SNI pattern in mouse retinas was similar to that seen in goldfish under matching illumination protocols. Further, there was a drastic reduction in overall S-nitrosylated protein immunoreactivity in light adapted retinas from mice lacking neuronal nitric oxide synthase.
Our results suggest that the extent of S-nitrosylation in goldfish and mouse retina depends on the intensity of illumination, consistent with intensity dependent production/release of NO in the retina. Our data also suggest that S-nitrosylation might be influencing retinal signal processing at multiple stages during light adaptation.
This PDF is available to Subscribers Only