What question did this study set out to answer?

Determine the ionic basis of prolonged outward currents in Helix aspersa neurones and assess whether potassium channel activation depends on calcium influx.

July 1, 1975The Journal of PhysiologyOpen Access

Potassium activation in Helix aspersa neurones under voltage clamp: a component mediated by calcium influx.

View Full Paper

Ask AI

Bookmark

Authors

RMRobert W. MeechUniversity of Bristol NSN. B. StandenLa Trobe University

Discussion

Member takes

Overview

Electrophysiological study reveals calcium influx activates outward potassium currents in snail neurones, indicating dual mechanisms govern membrane repolarization.

Key Points

Determine the ionic basis of prolonged outward currents in Helix aspersa neurones and assess whether potassium channel activation depends on calcium influx.
Applied two-electrode voltage clamp recordings to Helix aspersa neurones (specifically cell A) during depolarizing command pulses.
Manipulated extracellular ions using calcium-free, magnesium-supplemented saline and evaluated pharmacological blockers including cobalt (10 mM), lanthanum (1 mM), D-600, iproveratril, and tetraethylammonium.
Cobalt (10 mM) reversibly reduced outward potassium currents by 25% to 50%, while calcium-free saline abolished the characteristic 'n'-shaped current-voltage relationship and suppressed the slower tail current component.
Both voltage-dependent and calcium-activated potassium channels were blocked by tetraethylammonium with an identical dissociation constant of approximately 10 mM.
Resting intracellular ionized calcium was estimated between 3 × 10⁻⁸ M and 8 × 10⁻⁸ M, with the calcium null potential shifting 30 mV per tenfold change in external calcium.

Cite This Study

Meech et al. (1975) studied this question.

synapsesocial.com/papers/6a17176eb13aec50ea6bdb87 https://doi.org/10.1113/jphysiol.1975.sp011012

View Full Paper

Ask AI

Bookmark

July 1, 1975The Journal of PhysiologyOpen Access

Potassium activation in Helix aspersa neurones under voltage clamp: a component mediated by calcium influx.

View Full Paper

Ask AI

Bookmark

Authors

RMRobert W. MeechUniversity of Bristol NSN. B. StandenLa Trobe University

Discussion

Member takes

Overview

Electrophysiological study reveals calcium influx activates outward potassium currents in snail neurones, indicating dual mechanisms govern membrane repolarization.

Key Points

Determine the ionic basis of prolonged outward currents in Helix aspersa neurones and assess whether potassium channel activation depends on calcium influx.
Applied two-electrode voltage clamp recordings to Helix aspersa neurones (specifically cell A) during depolarizing command pulses.
Manipulated extracellular ions using calcium-free, magnesium-supplemented saline and evaluated pharmacological blockers including cobalt (10 mM), lanthanum (1 mM), D-600, iproveratril, and tetraethylammonium.
Cobalt (10 mM) reversibly reduced outward potassium currents by 25% to 50%, while calcium-free saline abolished the characteristic 'n'-shaped current-voltage relationship and suppressed the slower tail current component.
Both voltage-dependent and calcium-activated potassium channels were blocked by tetraethylammonium with an identical dissociation constant of approximately 10 mM.
Resting intracellular ionized calcium was estimated between 3 × 10⁻⁸ M and 8 × 10⁻⁸ M, with the calcium null potential shifting 30 mV per tenfold change in external calcium.

Cite This Study

Meech et al. (1975) studied this question.

synapsesocial.com/papers/6a17176eb13aec50ea6bdb87 https://doi.org/10.1113/jphysiol.1975.sp011012

Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

View Full Paper

Ask AI

Bookmark