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Elementary and macroscopic light-induced currents and their Ca(2+)-dependence in the photoreceptors of Periplaneta americana

Immonen, Esa-Ville LU ; Krause, S.; Krause, Y.; Frolov, R.; Vahasoyrinki, M. T. and Weckstrom, M. (2014) In Frontiers in Physiology 5. p.153-153
Abstract
In a microvillar photoreceptor, absorption of an incident photon initiates a phototransduction reaction that generates a depolarizing light-induced current (LIC) in the microvillus. Although in-depth knowledge about these processes in photoreceptors of the fruitfly Drosophila is available, not much is known about their nature in other insect species. Here, we present description of some basic properties of both elementary and macroscopic LICs and their Ca(2+)-dependence in the photoreceptors of a dark-active species, the cockroach Periplaneta americana. Cockroach photoreceptors respond to single photon absorptions by generating quantum bumps with about 5-fold larger amplitudes than in Drosophila. At the macroscopic current level, cockroach... (More)
In a microvillar photoreceptor, absorption of an incident photon initiates a phototransduction reaction that generates a depolarizing light-induced current (LIC) in the microvillus. Although in-depth knowledge about these processes in photoreceptors of the fruitfly Drosophila is available, not much is known about their nature in other insect species. Here, we present description of some basic properties of both elementary and macroscopic LICs and their Ca(2+)-dependence in the photoreceptors of a dark-active species, the cockroach Periplaneta americana. Cockroach photoreceptors respond to single photon absorptions by generating quantum bumps with about 5-fold larger amplitudes than in Drosophila. At the macroscopic current level, cockroach photoreceptors responded to light with variable sensitivity and current waveform. This variability could be partially attributed to differences in whole-cell capacitance. Transient LICs, both elementary and macroscopic, showed only moderate dependence on extracellular Ca(2+). However, with long light pulses, response inactivation was largely abolished and the overall size of LICs increased when extracellular Ca(2+) was omitted. Finally, by determining relative ionic permeabilities from reversals of LICs, we demonstrate that when compared to Drosophila, cockroach light-gated channels are only moderately Ca(2+)-selective. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Frontiers in Physiology
volume
5
pages
153 - 153
publisher
Frontiers
external identifiers
  • scopus:84901003769
ISSN
1664-042X
DOI
10.3389/fphys.2014.00153
language
English
LU publication?
no
id
82762abe-294f-4a1c-b36a-503ed2504a48 (old id 5431794)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/24795648
date added to LUP
2015-05-25 14:21:57
date last changed
2017-08-27 04:39:41
@article{82762abe-294f-4a1c-b36a-503ed2504a48,
  abstract     = {In a microvillar photoreceptor, absorption of an incident photon initiates a phototransduction reaction that generates a depolarizing light-induced current (LIC) in the microvillus. Although in-depth knowledge about these processes in photoreceptors of the fruitfly Drosophila is available, not much is known about their nature in other insect species. Here, we present description of some basic properties of both elementary and macroscopic LICs and their Ca(2+)-dependence in the photoreceptors of a dark-active species, the cockroach Periplaneta americana. Cockroach photoreceptors respond to single photon absorptions by generating quantum bumps with about 5-fold larger amplitudes than in Drosophila. At the macroscopic current level, cockroach photoreceptors responded to light with variable sensitivity and current waveform. This variability could be partially attributed to differences in whole-cell capacitance. Transient LICs, both elementary and macroscopic, showed only moderate dependence on extracellular Ca(2+). However, with long light pulses, response inactivation was largely abolished and the overall size of LICs increased when extracellular Ca(2+) was omitted. Finally, by determining relative ionic permeabilities from reversals of LICs, we demonstrate that when compared to Drosophila, cockroach light-gated channels are only moderately Ca(2+)-selective.},
  author       = {Immonen, Esa-Ville and Krause, S. and Krause, Y. and Frolov, R. and Vahasoyrinki, M. T. and Weckstrom, M.},
  issn         = {1664-042X},
  language     = {eng},
  pages        = {153--153},
  publisher    = {Frontiers},
  series       = {Frontiers in Physiology},
  title        = {Elementary and macroscopic light-induced currents and their Ca(2+)-dependence in the photoreceptors of Periplaneta americana},
  url          = {http://dx.doi.org/10.3389/fphys.2014.00153},
  volume       = {5},
  year         = {2014},
}