The effect of intensity and duration on the light-induced sodium and potassium currents in the Hermissenda type B photoreceptor

Kim T Blackwell

doi:10.1523/jneurosci.22-10-04217.2002

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The effect of intensity and duration on the light-induced sodium and potassium currents in the Hermissenda type B photoreceptor

Journal article

Open access

Peer reviewed

The effect of intensity and duration on the light-induced sodium and potassium currents in the Hermissenda type B photoreceptor

Kim T Blackwell

The Journal of neuroscience, Vol.22(10), pp.4217-4228

05/15/2002

DOI: 10.1523/jneurosci.22-10-04217.2002

PMCID: PMC6757656

PMID: 12019339

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Abstract

Light duration and intensity influence classical conditioning in Hermissenda through their effects on the light-induced currents. Furthermore, the contribution of voltage-dependent potassium currents to the long-lasting depolarization in type B photoreceptors depends on light-induced currents active at resting potentials. Thus, the present study measures the effect of holding potential, duration, and intensity on the light-induced currents in discontinuous single-electrode voltage clamp mode. Three distinct current components are distinguished by their temporal and voltage characteristics and sensitivity to pharmacological agents. One current component is a transient sodium current, I(Nalgt); another is a plateau sodium current, I(plateau), which persists for the duration of the light stimulus. Substitution of trimethylammonium chloride for sodium reduces both currents equally, suggesting that I(plateau) represents partial inactivation of I(Nalgt). The third current component is a prolonged reduction in potassium currents, I(Klgt); it is accompanied by an increase in input resistance, and it appears at potentials close to rest. An increase in light duration or intensity causes an increase in the peak conductance of both I(Nalgt) and I(Klgt). Latency of I(Nalgt) is decreased by intensity, whereas rise time is increased by duration. An increase in light duration or intensity causes an increase in the time-to-peak and duration of I(Klgt). Characteristics of these currents suggest that I(Klgt) is responsible for the long-lasting depolarization seen after light termination, and thus plays a role in classical conditioning.

Action Potentials - drug effects

Action Potentials - physiology

Action Potentials - radiation effects

Animals

Axotomy

Barium - pharmacology

Calcium - pharmacology

Dark Adaptation - physiology

Dose-Response Relationship, Radiation

Ganglionic Stimulants - pharmacology

In Vitro Techniques

Light

Membrane Potentials - drug effects

Membrane Potentials - physiology

Membrane Potentials - radiation effects

Mollusca

Patch-Clamp Techniques

Photic Stimulation - methods

Photoreceptor Cells, Invertebrate - drug effects

Photoreceptor Cells, Invertebrate - metabolism

Photoreceptor Cells, Invertebrate - radiation effects

Physical Stimulation

Potassium - metabolism

Reaction Time - drug effects

Reaction Time - radiation effects

Sodium - metabolism

Sodium Channel Blockers - pharmacology

Vision, Ocular - physiology

Details

Title: Subtitle: The effect of intensity and duration on the light-induced sodium and potassium currents in the Hermissenda type B photoreceptor
Creators: Kim T Blackwell - George Mason University
Resource Type: Journal article
Publication Details: The Journal of neuroscience, Vol.22(10), pp.4217-4228
DOI: 10.1523/jneurosci.22-10-04217.2002
PMID: 12019339
PMCID: PMC6757656
NLM abbreviation: J Neurosci
ISSN: 0270-6474
eISSN: 1529-2401
Grant note: K21 MH001141 / NIMH NIH HHS K21 MH01141 / NIMH NIH HHS
Language: English
Date published: 05/15/2002
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Iowa Neuroscience Institute
Record Identifier: 9984446537502771

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8 Times Cited - Web of Science