Dumke CL, Arshavsky VY, Calvert PD, Bownds MD, Pugh EN., Jr Rod outer segment structure influences the apparent kinetic parameters of cyclic GMP phosphodiesterase.Ganglion cell performance at absolute threshold in toad retina: effects of dark events in rods. Relaxation and fluctuations of membrane currents that flow through drug-operated channels. Extrusion of calcium from rod outer segments is driven by both sodium and potassium gradients. Cervetto L, Lagnado L, Perry RJ, Robinson DW, McNaughton PA.Expression in bacteria of functional inhibitory subunit of retinal rod cGMP phosphodiesterase. Functional regions of the inhibitory subunit of retinal rod cGMP phosphodiesterase identified by site-specific mutagenesis and fluorescence spectroscopy. Patch-clamp recordings of the light-sensitive dark noise in retinal rods from the lizard and frog. The photocurrent, noise and spectral sensitivity of rods of the monkey Macaca fascicularis. Electrical properties of the light-sensitive conductance of rods of the salamander Ambystoma tigrinum. Two components of electrical dark noise in toad retinal rod outer segments. Responses of retinal rods to single photons. The membrane current of single rod outer segments.
Responses to single quanta of light in retinal ganglion cells of the cat. Retinal origins of the temperature effect on absolute visual sensitivity in frogs. Low retinal noise in animals with low body temperature allows high visual sensitivity. Aho AC, Donner K, Hydén C, Larsen LO, Reuter T.Links to PubMed are also available for Selected References. Get a printable copy (PDF file) of the complete article (3.4M), or click on a page image below to browse page by page.
DARK NOISE FULL
Full textįull text is available as a scanned copy of the original print version. Quantitative analysis of the noise provided estimates of the rate constants for spontaneous PDE activation and deactivation and the catalytic activity of a single PDE molecule in situ. The addition of recombinant gamma, the inhibitory subunit of PDE, did not suppress the noise, indicating that endogenous gamma does not completely dissociate from the catalytic subunit of PDE during spontaneous activation. These experiments indicate that the noise is generated by spontaneous activation of cGMP phosphodiesterase (PDE) through a process that does not involve transducin. Selectively disabling different elements of the phototransduction cascade allowed examination of their contributions to the continuous noise. The continuous noise was separated from noise due to thermal activation of rhodopsin and to transitions in the cGMP-activated channels. Membrane current was recorded from intact, isolated rods or truncated, internally dialyzed rod outer segments. We investigated the molecular mechanism of the continuous component of the electrical dark noise in toad rods. Noise in the rod photoreceptors limits the ability of the dark-adapted visual system to detect dim lights.
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