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Updated: Jul 30, 2026

Recording Light-evoked Postsynaptic Responses in Neurons in Dark-adapted, Mouse Retinal Slice Preparations Using Patch Clamp Techniques
Published on: February 11, 2015
cGMP-gated conductance in retinal bipolar cells is suppressed by the photoreceptor transmitter
Abstract:
Transmitter release from photoreceptors is decreased by light, resulting in a conductance increase in depolarizing bipolar cells. Addition of exogenous cGMP through a patch pipette to depolarizing bipolar cells from slices of dark-adapted tiger salamander retina resulted in an enhancement of the light response. This enhancement was blocked by GTP-gamma-S and dipyridamole, an inhibitor of phosphodiesterase. GTP-gamma-S and dipyridamole also blocked responses to exogenously applied 2-amino-4-phosphonobutyrate (APB), the glutamate agonist selective for this receptor. These data support the hypothesis that the postsynaptic receptor is linked via a G protein to a phosphodiesterase. The binding of glutamate or APB to the receptor suppresses a cGMP-activated current by increasing the rate of cyclic nucleotide hydrolysis.
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