Selectivity of edta-modified calcium channels to monovalent cations

The characteristics of slow inward sodium currents arising in response to membrane depolarization were studied in experiments on isolated dialyzed neurons of the snail Helix pomatia when the calcium-chelating agent EDTA was added to the calcium-free external solution. It is postulated on the basis o...

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Bibliographic Details
Published in:Neurophysiology (New York) 1983, Vol.14 (5), p.359-365
Main Authors: Kostyuk, P. G., Shuba, Ya. M.
Format: Article
Language:English
Subjects:
Helix pomatia
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Summary:The characteristics of slow inward sodium currents arising in response to membrane depolarization were studied in experiments on isolated dialyzed neurons of the snail Helix pomatia when the calcium-chelating agent EDTA was added to the calcium-free external solution. It is postulated on the basis of these data that the calcium channels have a principal selective filter similar to that of sodium channels, but also an additional binding site for bivalent cations, which prevents entry of monovalent cations into the channel. The addition of calcium-chelating agents to the calcium-free external solution liberates this site and thereby modifies the calcium channel into a sodium channel.
ISSN:0090-2977
1573-9007
DOI:10.1007/BF01073217