Evidence for a distinct light-induced calcium-dependent potassium current in Hermissenda crassicornis

K T Blackwell

doi:10.1023/A:1008919924579

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Evidence for a distinct light-induced calcium-dependent potassium current in Hermissenda crassicornis

Journal article

Peer reviewed

Evidence for a distinct light-induced calcium-dependent potassium current in Hermissenda crassicornis

K T Blackwell

Journal of computational neuroscience, Vol.9(2), pp.149-170

09/01/2000

DOI: 10.1023/A:1008919924579

PMID: 11030519

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Abstract

A model of phototransduction is developed as a first step toward a model for investigating the critical interaction of light and turbulence stimuli within the type B photoreceptor of Hermissenda crassicronis. The model includes equations describing phototransduction, release of calcium from intracellular stores, and other calcium regulatory mechanisms, as well as equations describing ligand-gating of a rhabdomeric sodium current. The model is used to determine the sources of calcium in the soma, whether calcium or IP3 is a plausible ligand of the light-induced sodium current, and whether the light-induced potassium current is equivalent to the calcium-dependent potassium current activated by light-induced calcium release. Simulations show that the early light-induced calcium elevation is due to influx through voltage-dependent channels, whereas the later calcium elevation is due to release from intracellular stores. Simulations suggest that the ligand of the fast, light-induced sodium current is IP3 but that there is a smaller, prolonged component of the light-induced sodium current that is activated by calcium. In the model, the calcium-dependent potassium current, located in the soma, is activated only slightly by light-induced calcium elevation, leading to the prediction that a calcium-dependent potassium current, active at resting potential, is located in the rhabdomere and is responsible for the light-induced potassium current.

Animals

Calcium - metabolism

Calcium - pharmacology

Calcium Signaling - drug effects

Calcium Signaling - physiology

Cell Membrane - drug effects

Cell Membrane - metabolism

Cell Membrane - ultrastructure

Membrane Potentials - drug effects

Membrane Potentials - physiology

Models, Animal

Models, Neurological

Mollusca - anatomy & histology

Mollusca - physiology

Photic Stimulation

Photoreceptor Cells, Invertebrate - drug effects

Photoreceptor Cells, Invertebrate - metabolism

Photoreceptor Cells, Invertebrate - ultrastructure

Potassium Channels - drug effects

Potassium Channels - metabolism

Potassium Channels - ultrastructure

Sodium Channels - drug effects

Sodium Channels - metabolism

Vision, Ocular - drug effects

Vision, Ocular - physiology

Details

Title: Subtitle: Evidence for a distinct light-induced calcium-dependent potassium current in Hermissenda crassicornis
Creators: K T Blackwell - George Mason University
Resource Type: Journal article
Publication Details: Journal of computational neuroscience, Vol.9(2), pp.149-170
DOI: 10.1023/A:1008919924579
PMID: 11030519
NLM abbreviation: J Comput Neurosci
ISSN: 0929-5313
eISSN: 1573-6873
Grant note: K21 MH001141 / NIMH NIH HHS
Language: English
Date published: 09/01/2000
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Iowa Neuroscience Institute
Record Identifier: 9984446266202771

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