Related Experiment Video
Updated: Feb 15, 2026

Single-cell Suction Recordings from Mouse Cone Photoreceptors
Published on: January 5, 2010
Pannexin 1 Is Critically Involved in Feedback from Horizontal Cells to Cones
Valentina Cenedese1, Wim de Graaff1, Tamás Csikós1
1Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, Netherlands.
Abstract:
Retinal horizontal cells (HCs) feed back negatively to cone photoreceptors and in that way generate the center/surround organization of bipolar cell receptive fields. The mechanism by which HCs inhibit photoreceptors is a matter of debate. General consensus exists that horizontal cell activity leads to the modulation of the cone Ca-current. This modulation has two components, one fast and the other slow. Several mechanisms for this modulation have been proposed: a fast ephaptic mechanism, and a slow pH mediated mechanism. Here we test the hypothesis that the slow negative feedback signal from HCs to cones is mediated by Panx1 channels expressed at the tips of the dendrites of horizontal cell. We generated zebrafish lacking Panx1 and found that the slow component of the feedback signal was strongly reduced in the mutants showing that Panx1 channels are a fundamental part of the negative feedback pathway from HCs to cones.
Related Concept Videos
Feedback Inhibition
Cell Signaling Feedback Loops
Negative feedback loops
Most signaling systems have negative feedback loops that can perform different functions such as output limiter, and adaptation.
Output limiter
Upon receiving an input signal, the cellular response rapidly increases until a threshold is reached. Beyond this threshold, a negative feedback loop...
Feedback Loops
Effects of feedback
Feedback significantly modifies the gain of a control system. The gain of a system without feedback is altered by a factor of one plus GH, where G represents...
Feedback control systems
Linear feedback systems are theoretical models that simplify analysis and design. These systems operate under the principle that their output is directly proportional to their input within certain ranges. For instance, an amplifier in a control system behaves linearly as long as the input signal remains within a specific range. However, most physical systems exhibit inherent nonlinearity...
Facial Feedback Hypothesis

