Analysis of leak current properties in the lobster stretch receptor neurone
Experiments were performed to characterize the so-called leak current of the slowly adapting stretch receptor neurone of the European lobster with respect to its ionic basis, its kinetics and its pharmacology. Estimates of the leak current were obtained by subtraction of a Na-K pump current and of a...
Published in: | Acta Physiologica Scandinavica |
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Language: | English |
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Wiley-Blackwell
1996
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Online Access: | https://lup.lub.lu.se/record/940a0180-afc7-4b7a-8aa7-944e33fae1ff https://doi.org/10.1046/j.1365-201X.1996.510271000.x |
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ftulundlup:oai:lup.lub.lu.se:940a0180-afc7-4b7a-8aa7-944e33fae1ff 2024-02-11T10:03:38+01:00 Analysis of leak current properties in the lobster stretch receptor neurone Theander, S Fåhraeus, C Grampp, W 1996-08 https://lup.lub.lu.se/record/940a0180-afc7-4b7a-8aa7-944e33fae1ff https://doi.org/10.1046/j.1365-201X.1996.510271000.x eng eng Wiley-Blackwell https://lup.lub.lu.se/record/940a0180-afc7-4b7a-8aa7-944e33fae1ff http://dx.doi.org/10.1046/j.1365-201X.1996.510271000.x pmid:8869733 scopus:0029783195 Acta Physiologica Scandinavica; 157(4), pp 493-509 (1996) ISSN: 0001-6772 Animals Chlorides/metabolism Cobalt/pharmacology In Vitro Techniques Ion Transport/drug effects Kinetics Mechanoreceptors/metabolism Membrane Potentials/drug effects Nephropidae/metabolism Neurons/metabolism Potassium/metabolism Sodium/metabolism Sodium-Potassium-Exchanging ATPase/metabolism contributiontojournal/article info:eu-repo/semantics/article text 1996 ftulundlup https://doi.org/10.1046/j.1365-201X.1996.510271000.x 2024-01-17T23:29:35Z Experiments were performed to characterize the so-called leak current of the slowly adapting stretch receptor neurone of the European lobster with respect to its ionic basis, its kinetics and its pharmacology. Estimates of the leak current were obtained by subtraction of a Na-K pump current and of an unspecific impalement current from a non-dynamic ('instantaneous') current, recorded in a voltage range from approximately -120 to approximately -30 mV, after blockage of spike-generating currents and a hyperpolarization-activated inwardly rectifying current (Q-current). The leak current, estimated in this way, was seen to reverse direction at the cell's K+ equilibrium voltage, thus indicating that it is carried by K+ passing through channels which, also, proved to be permeable to Rb+ and NH4+, but not permeable to Na+ or Cl- to any significant extent. Kinetically, the leak current was found to be characterized by being enhanced by increases in extracellular K+ and by being subject to outward rectification, most distinctly at elevated extracellular [K+]. In quantitative terms, these kinetic properties could be accounted for by a mathematical model comprising (1) a one-site two-barrier Eyring formulation describing ion permeation through membrane channels and (2) an ordinary dose-response relationship describing the channel-opening effect of K+ at an extracellular regulatory site. Pharmacologically, the leak current proved to be distinguished by being reversibly blockable, in a non-voltage dependent manner, by CO2+ (Kd = 0.9 mM, Hill coefficient 1.1) and procaine, but not by Ba2+, Gd3+, bupivacaine (a local anesthetic), or other K+ channel blockers such as TEA, 4-AP and Cs+. It is concluded that, in native unimpaled cells, the K+ carried leak current (1) is setting the resting voltage together with the (mainly) Na(+)-carried Q-current and the Na-K pump current, (2) is determining the cell's firing threshold, together with the spike generating currents, and (3) is also stabilizing the cell's membrane excitability in ... Article in Journal/Newspaper European lobster Lund University Publications (LUP) The Spike ENVELOPE(-37.317,-37.317,-54.017,-54.017) Acta Physiologica Scandinavica 157 4 493 509 |
institution |
Open Polar |
collection |
Lund University Publications (LUP) |
op_collection_id |
ftulundlup |
language |
English |
topic |
Animals Chlorides/metabolism Cobalt/pharmacology In Vitro Techniques Ion Transport/drug effects Kinetics Mechanoreceptors/metabolism Membrane Potentials/drug effects Nephropidae/metabolism Neurons/metabolism Potassium/metabolism Sodium/metabolism Sodium-Potassium-Exchanging ATPase/metabolism |
spellingShingle |
Animals Chlorides/metabolism Cobalt/pharmacology In Vitro Techniques Ion Transport/drug effects Kinetics Mechanoreceptors/metabolism Membrane Potentials/drug effects Nephropidae/metabolism Neurons/metabolism Potassium/metabolism Sodium/metabolism Sodium-Potassium-Exchanging ATPase/metabolism Theander, S Fåhraeus, C Grampp, W Analysis of leak current properties in the lobster stretch receptor neurone |
topic_facet |
Animals Chlorides/metabolism Cobalt/pharmacology In Vitro Techniques Ion Transport/drug effects Kinetics Mechanoreceptors/metabolism Membrane Potentials/drug effects Nephropidae/metabolism Neurons/metabolism Potassium/metabolism Sodium/metabolism Sodium-Potassium-Exchanging ATPase/metabolism |
description |
Experiments were performed to characterize the so-called leak current of the slowly adapting stretch receptor neurone of the European lobster with respect to its ionic basis, its kinetics and its pharmacology. Estimates of the leak current were obtained by subtraction of a Na-K pump current and of an unspecific impalement current from a non-dynamic ('instantaneous') current, recorded in a voltage range from approximately -120 to approximately -30 mV, after blockage of spike-generating currents and a hyperpolarization-activated inwardly rectifying current (Q-current). The leak current, estimated in this way, was seen to reverse direction at the cell's K+ equilibrium voltage, thus indicating that it is carried by K+ passing through channels which, also, proved to be permeable to Rb+ and NH4+, but not permeable to Na+ or Cl- to any significant extent. Kinetically, the leak current was found to be characterized by being enhanced by increases in extracellular K+ and by being subject to outward rectification, most distinctly at elevated extracellular [K+]. In quantitative terms, these kinetic properties could be accounted for by a mathematical model comprising (1) a one-site two-barrier Eyring formulation describing ion permeation through membrane channels and (2) an ordinary dose-response relationship describing the channel-opening effect of K+ at an extracellular regulatory site. Pharmacologically, the leak current proved to be distinguished by being reversibly blockable, in a non-voltage dependent manner, by CO2+ (Kd = 0.9 mM, Hill coefficient 1.1) and procaine, but not by Ba2+, Gd3+, bupivacaine (a local anesthetic), or other K+ channel blockers such as TEA, 4-AP and Cs+. It is concluded that, in native unimpaled cells, the K+ carried leak current (1) is setting the resting voltage together with the (mainly) Na(+)-carried Q-current and the Na-K pump current, (2) is determining the cell's firing threshold, together with the spike generating currents, and (3) is also stabilizing the cell's membrane excitability in ... |
format |
Article in Journal/Newspaper |
author |
Theander, S Fåhraeus, C Grampp, W |
author_facet |
Theander, S Fåhraeus, C Grampp, W |
author_sort |
Theander, S |
title |
Analysis of leak current properties in the lobster stretch receptor neurone |
title_short |
Analysis of leak current properties in the lobster stretch receptor neurone |
title_full |
Analysis of leak current properties in the lobster stretch receptor neurone |
title_fullStr |
Analysis of leak current properties in the lobster stretch receptor neurone |
title_full_unstemmed |
Analysis of leak current properties in the lobster stretch receptor neurone |
title_sort |
analysis of leak current properties in the lobster stretch receptor neurone |
publisher |
Wiley-Blackwell |
publishDate |
1996 |
url |
https://lup.lub.lu.se/record/940a0180-afc7-4b7a-8aa7-944e33fae1ff https://doi.org/10.1046/j.1365-201X.1996.510271000.x |
long_lat |
ENVELOPE(-37.317,-37.317,-54.017,-54.017) |
geographic |
The Spike |
geographic_facet |
The Spike |
genre |
European lobster |
genre_facet |
European lobster |
op_source |
Acta Physiologica Scandinavica; 157(4), pp 493-509 (1996) ISSN: 0001-6772 |
op_relation |
https://lup.lub.lu.se/record/940a0180-afc7-4b7a-8aa7-944e33fae1ff http://dx.doi.org/10.1046/j.1365-201X.1996.510271000.x pmid:8869733 scopus:0029783195 |
op_doi |
https://doi.org/10.1046/j.1365-201X.1996.510271000.x |
container_title |
Acta Physiologica Scandinavica |
container_volume |
157 |
container_issue |
4 |
container_start_page |
493 |
op_container_end_page |
509 |
_version_ |
1790599942580994048 |