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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1983 Oct;80(19):6110–6113. doi: 10.1073/pnas.80.19.6110

Acetylcholine receptor channel ionic selectivity: ions experience an aqueous environment.

C A Lewis, C F Stevens
PMCID: PMC534370  PMID: 6310616

Abstract

Alkali metal and alkaline earth cations pass readily through the acetylcholine receptor channel. Monovalent cations with larger crystal radii are more permeant than ones with smaller radii. For divalent ions, this selectivity sequence is reversed: smaller ions are more permeant than larger ones. This reversal in selectivity sequence with change of valence from 1 to 2 can be naturally accounted for by electrostatic interactions between the ion and its environment in the selectivity region of the channel. For monovalent ions, ion-dipole interactions dominate, and, for divalent ions, ion-induced dipole interactions are more important. The sign of these two types of effects is opposite and produces the reversal in the selectivity sequence. The magnitude of electrostatic interactions can be estimated from experimental data and suggests that the permeating ion's environment in the selectivity region of the channel is essentially like that in free water.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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