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Mechanisms Of Lateral-Inhibitory Feedback From Horizontal Cells To Cone Photoreceptors At The First Synapse Of The Retina, Ted J. Warren
Mechanisms Of Lateral-Inhibitory Feedback From Horizontal Cells To Cone Photoreceptors At The First Synapse Of The Retina, Ted J. Warren
Theses & Dissertations
Polarization of the horizontal cell (HC) membrane potential causes changes in the synaptic cleft pH that result in inhibitory feedback from HCs to cone photoreceptors (PRs). HCs average signals from many PRs and so negative feedback onto PR terminals from HCs subtracts the average luminance of the visual scene from the light responses of an individual cone. This feedback operates by changing the voltage-dependence and amplitude of the L-type Ca2+ current (ICa) that regulates synaptic release. Feedback regulation of PR Ca2+ channels involves protons but the mechanism by which this pH change occurs is unclear. We …