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Updated: Jun 20, 2026

Transretinal ERG Recordings from Mouse Retina: Rod and Cone Photoresponses
Published on: March 14, 2012
Complementary conductance changes by IKx and Ih contribute to membrane impedance stability during the rod light
1Department of Bioengineering, Rice University, Houston, TX, USA. andrew.barrow@bcm.edu
Abstract:
In addition to the HCN1 channels that mediate the h current, the Kx current also performs signal filtering in rod photoreceptors. This current is known to be mediated by potassium channels and has similarities to the neuronal M current and EAG potassium channels. Although it is known that in filtering the light response of rods, I(h) and I(Kx) undergo complementary conductance changes, the qualities and significance of these changes are not clear. Here we present an analysis demonstrating the filtering effect of HCN1 channels in salamander rods when I(Kx) is blocked, and a simulation of the rod light response showing the magnitude and time course of the conductance changes by both currents. From this analysis, we propose that the purpose of opposing conductance changes by I(h) and I(Kx) may be to optimize the lateral propagation of signals through gap junctions in the rod network.
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