GABA-mediated negative feedback from horizontal cells to cones in carp retina

In the isolated, perfused retina of the carp, properties of the feedback pathway from horizontal cells to cones were investigated by means of electrophysiological and neuropharmacological methods. When horizontal cells were hyperpolarized by illumination with an annulus, a depolarizing synaptic pote...

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Bibliographic Details
Published inJapanese journal of physiology Vol. 32; no. 6; p. 911
Main Authors Murakami, M, Shimoda, Y, Nakatani, K, Miyachi, E, Watanabe, S
Format Journal Article
LanguageEnglish
Published Japan 1982
Subjects
Animals
Carps
Electrophysiology
Feedback
gamma-Aminobutyric Acid - pharmacology
In Vitro Techniques
Perfusion
Photoreceptor Cells - physiology
Retina - physiology
Synapses - physiology
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Summary:In the isolated, perfused retina of the carp, properties of the feedback pathway from horizontal cells to cones were investigated by means of electrophysiological and neuropharmacological methods. When horizontal cells were hyperpolarized by illumination with an annulus, a depolarizing synaptic potential was produced in cones at the center of the annulus, suggesting that horizontal cells receive inputs from cones and exert a negative feedback to cones. On the other hand, a hyperpolarization (EPSP) was induced in horizontal cells by application of a transretinal current pulse, which activated the release of transmitter from the photoreceptor terminals. The IPSP was abolished when the retina was perfused with a GABA-containing Ringer solution, because of desensitization of the feedback synapse. GABA also hyperpolarized the cone membrane, indicating the presence of a GABA-sensitive site in the cone. These results suggest that the GABA-mediated negative feedback operates from horizontal cells to cones in the dark, and ceases its function in the light.
ISSN:0021-521X
DOI:10.2170/jjphysiol.32.911