Dependence of the acid-sensitive ion channel, ASIC1a, on extracellular Ca(2+) ions

The early H(+)-induced current in the embryonic spinal cord neurone depends on extracellular Ca(2+) for its function. We have studied the Ca(2+)-dependence of homo- and heteromultimeric acid-sensing ion channels (ASICs) expressed in Cos cells. It was found that single-channel conductance of both the...

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Bibliographic Details
Published in:Brain research 2001-05, Vol.900 (2), p.277-281
Main Authors: de Weille, J, Bassilana, F
Format: Article
Language:English
Subjects:
Acid Sensing Ion Channels
Amiloride - pharmacology
Animals
Calcium - metabolism
COS Cells
Dose-Response Relationship, Drug
Electric Conductivity
Extracellular Space - metabolism
Hydrogen-Ion Concentration
Ions
Membrane Potentials - physiology
Membrane Proteins
Nerve Tissue Proteins
Osmolar Concentration
Protein Isoforms - metabolism
Protein Isoforms - physiology
Sodium Channel Blockers
Sodium Channels - drug effects
Sodium Channels - metabolism
Sodium Channels - physiology
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Summary:The early H(+)-induced current in the embryonic spinal cord neurone depends on extracellular Ca(2+) for its function. We have studied the Ca(2+)-dependence of homo- and heteromultimeric acid-sensing ion channels (ASICs) expressed in Cos cells. It was found that single-channel conductance of both the ASIC2a and the ASIC1a channel is reduced at membrane potentials more negative than -40 mV by elevated extracellular Ca(2+). Due to this effect on unitary currents, the macroscopic ASIC2a peak current at -60 mV decreases gradually with rising extracellular Ca(2+) concentration. In addition, the macroscopic ASIC1a current is very small at low extracellular Ca(2+) and increases with rising Ca(2+) up to 5 mM before decreasing again at still higher concentrations of extracellular Ca(2+).
ISSN:0006-8993
1872-6240
DOI:10.1016/S0006-8993(01)02345-9