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Discrete Waves and Phototransduction in Voltage-damped Ventral Photoreceptors

Discrete waves in the voltage-clamped photoreceptor of Limulus are remarkably similar in all essential properties to those found in an unclamped cell. The latency distribution of discrete waves is not affected by considerable changes in the holding potential in a voltage-clamped cell. Both large and...

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Detalles Bibliográficos
Autores principales: Behbehani, Michael, Srebro, Richard
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1974
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2226171/
https://www.ncbi.nlm.nih.gov/pubmed/4846766
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author Behbehani, Michael
Srebro, Richard
author_facet Behbehani, Michael
Srebro, Richard
author_sort Behbehani, Michael
collection PubMed
description Discrete waves in the voltage-clamped photoreceptor of Limulus are remarkably similar in all essential properties to those found in an unclamped cell. The latency distribution of discrete waves is not affected by considerable changes in the holding potential in a voltage-clamped cell. Both large and small waves occur in voltage-clamped and unclamped cells and in approximately the same proportion. Large and small waves also share the same latency distributions and spectral sensitivity. We suggest that small waves may result from the activation of damaged membrane areas. Large waves have an average amplitude of approximately 5 nA in voltage-clamped photoreceptors. It probably requires several square microns of cell membrane to support this much photo-current. Thus the amplification inherent in the discrete wave process may involve spatial spread of activation from unimolecular dimensions to several square microns of cell membrane surface. Neither local current flow, nor pre-packaging of any transmitter substance appears to be involved in the amplification process. The possible mechanisms of the amplification are evaluated with relationship to the properties of discrete waves.
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spelling pubmed-22261712008-04-23 Discrete Waves and Phototransduction in Voltage-damped Ventral Photoreceptors Behbehani, Michael Srebro, Richard J Gen Physiol Article Discrete waves in the voltage-clamped photoreceptor of Limulus are remarkably similar in all essential properties to those found in an unclamped cell. The latency distribution of discrete waves is not affected by considerable changes in the holding potential in a voltage-clamped cell. Both large and small waves occur in voltage-clamped and unclamped cells and in approximately the same proportion. Large and small waves also share the same latency distributions and spectral sensitivity. We suggest that small waves may result from the activation of damaged membrane areas. Large waves have an average amplitude of approximately 5 nA in voltage-clamped photoreceptors. It probably requires several square microns of cell membrane to support this much photo-current. Thus the amplification inherent in the discrete wave process may involve spatial spread of activation from unimolecular dimensions to several square microns of cell membrane surface. Neither local current flow, nor pre-packaging of any transmitter substance appears to be involved in the amplification process. The possible mechanisms of the amplification are evaluated with relationship to the properties of discrete waves. The Rockefeller University Press 1974-08-01 /pmc/articles/PMC2226171/ /pubmed/4846766 Text en Copyright © 1974 by The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Article
Behbehani, Michael
Srebro, Richard
Discrete Waves and Phototransduction in Voltage-damped Ventral Photoreceptors
title Discrete Waves and Phototransduction in Voltage-damped Ventral Photoreceptors
title_full Discrete Waves and Phototransduction in Voltage-damped Ventral Photoreceptors
title_fullStr Discrete Waves and Phototransduction in Voltage-damped Ventral Photoreceptors
title_full_unstemmed Discrete Waves and Phototransduction in Voltage-damped Ventral Photoreceptors
title_short Discrete Waves and Phototransduction in Voltage-damped Ventral Photoreceptors
title_sort discrete waves and phototransduction in voltage-damped ventral photoreceptors
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2226171/
https://www.ncbi.nlm.nih.gov/pubmed/4846766
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