Cellular elements for seeing in the dark: voltage-dependent conductances in cockroach photoreceptors
(2012) In BMC Neuroscience 13. p.93-93- Abstract
- BACKGROUND: The importance of voltage-dependent conductances in sensory information processing is well-established in insect photoreceptors. Here we present the characterization of electrical properties in photoreceptors of the cockroach (Periplaneta americana), a nocturnal insect with a visual system adapted for dim light. RESULTS: Whole-cell patch-clamped photoreceptors had high capacitances and input resistances, indicating large photosensitive rhabdomeres suitable for efficient photon capture and amplification of small photocurrents at low light levels. Two voltage-dependent potassium conductances were found in the photoreceptors: a delayed rectifier type (KDR) and a fast transient inactivating type (KA). Activation of KDR occurred... (More)
- BACKGROUND: The importance of voltage-dependent conductances in sensory information processing is well-established in insect photoreceptors. Here we present the characterization of electrical properties in photoreceptors of the cockroach (Periplaneta americana), a nocturnal insect with a visual system adapted for dim light. RESULTS: Whole-cell patch-clamped photoreceptors had high capacitances and input resistances, indicating large photosensitive rhabdomeres suitable for efficient photon capture and amplification of small photocurrents at low light levels. Two voltage-dependent potassium conductances were found in the photoreceptors: a delayed rectifier type (KDR) and a fast transient inactivating type (KA). Activation of KDR occurred during physiological voltage responses induced by light stimulation, whereas KA was nearly fully inactivated already at the dark resting potential. In addition, hyperpolarization of photoreceptors activated a small-amplitude inward-rectifying (IR) current mediated at least partially by chloride. Computer simulations showed that KDR shapes light responses by opposing the light-induced depolarization and speeding up the membrane time constant, whereas KA and IR have a negligible role in the majority of cells. However, larger KA conductances were found in smaller and rapidly adapting photoreceptors, where KA could have a functional role. CONCLUSIONS: The relative expression of KA and KDR in cockroach photoreceptors was opposite to the previously hypothesized framework for dark-active insects, necessitating further comparative work on the conductances. In general, the varying deployment of stereotypical K+ conductances in insect photoreceptors highlights their functional flexibility in neural coding. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/5431803
- author
- Salmela, I. ; Immonen, Esa-Ville LU ; Frolov, R. ; Krause, S. ; Krause, Y. ; Vahasoyrinki, M. and Weckstrom, M.
- organization
- publishing date
- 2012
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Photoreceptor Cells, Photic Stimulation, Patch-Clamp Techniques, Biological, Models, Membrane Potentials/drug effects/*physiology, Light, In Vitro Techniques, Electric Stimulation, Computer Simulation, Cockroaches, Animals, Biophysical Phenomena/drug effects/*physiology, Invertebrate/*physiology, Potassium/metabolism, Potassium Channel Blockers/pharmacology, Potassium Channels/drug effects/*physiology, Tetraethylammonium/pharmacology
- in
- BMC Neuroscience
- volume
- 13
- pages
- 93 - 93
- publisher
- BioMed Central (BMC)
- external identifiers
-
- scopus:84864502309
- ISSN
- 1471-2202
- DOI
- 10.1186/1471-2202-13-93
- language
- English
- LU publication?
- yes
- id
- 8c427004-ad30-4493-98a5-898510029992 (old id 5431803)
- alternative location
- http://www.ncbi.nlm.nih.gov/pubmed/22867024
- date added to LUP
- 2016-04-04 09:13:53
- date last changed
- 2022-01-29 08:55:19
@article{8c427004-ad30-4493-98a5-898510029992,
abstract = {{BACKGROUND: The importance of voltage-dependent conductances in sensory information processing is well-established in insect photoreceptors. Here we present the characterization of electrical properties in photoreceptors of the cockroach (Periplaneta americana), a nocturnal insect with a visual system adapted for dim light. RESULTS: Whole-cell patch-clamped photoreceptors had high capacitances and input resistances, indicating large photosensitive rhabdomeres suitable for efficient photon capture and amplification of small photocurrents at low light levels. Two voltage-dependent potassium conductances were found in the photoreceptors: a delayed rectifier type (KDR) and a fast transient inactivating type (KA). Activation of KDR occurred during physiological voltage responses induced by light stimulation, whereas KA was nearly fully inactivated already at the dark resting potential. In addition, hyperpolarization of photoreceptors activated a small-amplitude inward-rectifying (IR) current mediated at least partially by chloride. Computer simulations showed that KDR shapes light responses by opposing the light-induced depolarization and speeding up the membrane time constant, whereas KA and IR have a negligible role in the majority of cells. However, larger KA conductances were found in smaller and rapidly adapting photoreceptors, where KA could have a functional role. CONCLUSIONS: The relative expression of KA and KDR in cockroach photoreceptors was opposite to the previously hypothesized framework for dark-active insects, necessitating further comparative work on the conductances. In general, the varying deployment of stereotypical K+ conductances in insect photoreceptors highlights their functional flexibility in neural coding.}},
author = {{Salmela, I. and Immonen, Esa-Ville and Frolov, R. and Krause, S. and Krause, Y. and Vahasoyrinki, M. and Weckstrom, M.}},
issn = {{1471-2202}},
keywords = {{Photoreceptor Cells; Photic Stimulation; Patch-Clamp Techniques; Biological; Models; Membrane Potentials/drug effects/*physiology; Light; In Vitro Techniques; Electric Stimulation; Computer Simulation; Cockroaches; Animals; Biophysical Phenomena/drug effects/*physiology; Invertebrate/*physiology; Potassium/metabolism; Potassium Channel Blockers/pharmacology; Potassium Channels/drug effects/*physiology; Tetraethylammonium/pharmacology}},
language = {{eng}},
pages = {{93--93}},
publisher = {{BioMed Central (BMC)}},
series = {{BMC Neuroscience}},
title = {{Cellular elements for seeing in the dark: voltage-dependent conductances in cockroach photoreceptors}},
url = {{http://dx.doi.org/10.1186/1471-2202-13-93}},
doi = {{10.1186/1471-2202-13-93}},
volume = {{13}},
year = {{2012}},
}