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Literature DB >> 2642011

Characterization of a voltage-gated K+ channel that accelerates the rod response to dim light.

Abstract

In this study a K+ current, IKx, in isolated salamander rod photoreceptors was characterized and its role in shaping small photovoltages was examined. IKx is a standing outward current of about 40 pA at -30 mV that deactivates slowly when the cell is hyperpolarized (tau max = 0.25 s). The voltage and time dependence of IKx are similar to that of M-current, but IKx can be distinguished from M-current because it is not suppressed by acetylcholine and is "blocked" by external Ba2+ in a surprising manner: the activation range of IKx is shifted strongly in the positive direction. Using current-clamp recordings and a computer simulation of the photo-response, we show that IKx figures prominently in setting the dark resting potential and accelerates the voltage response to small photocurrents.

Entities: Chemical

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Year: 1989 PMID： 2642011 PMCID： PMC3858083 DOI： 10.1016/0896-6273(89)90267-5

Source DB: PubMed Journal: Neuron ISSN： 0896-6273 Impact factor: 17.173

33 in total

Characterization of a voltage-gated K+ channel that accelerates the rod response to dim light.

1. The Sharpey-Schafer lecture. Ion channels and signal processing in the outer retina.

2. The electrical response of turtle cones to flashes and steps of light.

3. Rapidly activating hydrogen ion currents in perfused neurones of the snail, Lymnaea stagnalis.

4. Time- and voltage-dependent ionic components of the rod response.

5. The calcium current in inner segments of rods from the salamander (Ambystoma tigrinum) retina.

6. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.

7. Rapid dark adaptation of bullfrog rods is delayed by barium.

8. Location and function of voltage-sensitive conductances in retinal rods of the salamander, Ambystoma tigrinum.

9. Interaction of barium ions with potassium channels in squid giant axons.

10. Calcium and calcium-dependent chloride currents generate action potentials in solitary cone photoreceptors.

1. Properties and functional roles of hyperpolarization-gated currents in guinea-pig retinal rods.

2. Role of hyperpolarization-activated currents for the intrinsic dynamics of isolated retinal neurons.

3. Relation between potassium-channel kinetics and the intrinsic dynamics in isolated retinal bipolar cells.

4. Modulation of rod photoreceptor output by HCN1 channels is essential for regular mesopic cone vision.

5. The photovoltage of rods and cones in the dark-adapted mouse retina.

6. Cysteines control the N- and C-linker-dependent gating of KCNH1 potassium channels.

7. The photovoltage of macaque cone photoreceptors: adaptation, noise, and kinetics.

8. The contribution of cationic conductances to the potential of rod photoreceptors.

9. Multiple ion binding sites in Ih channels of rod photoreceptors from tiger salamanders.

10. Expression and localization of K channels KCNQ2 and KCNQ3 in the mammalian cochlea.