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Science 30 March 1979:
Vol. 203. no. 4387, pp. 1351 - 1352
DOI: 10.1126/science.424757
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Articles

Science, Vol 203, Issue 4387, 1351-1352
Copyright © 1979 by American Association for the Advancement of Science

articles

Membrane surface potential changes may alter drug interactions: an example, acetylcholine and curare

WG Van der Kloot and I Cohen

Curare is known to be less effective as an acetycholine antagonist when the divalent cation concentration of the extracellular solution is increased. This observation can be accounted for by the negative surface potential on the end plate; an increase in divalent cation concentration decreases the negativity of the surface potential and thereby lowers the concentrations of cations at the membrane-solution interface. The concentration of divalent cations, such as curare, will be reduced more than the concentration of univalent cations, such as acetylcholine. The observations can be accounted for by a surface potential of about -50 millivolts. The same principle can explain the reported actions of divalent cations on the affinity of receptors for acetylcholine. The effects of surface potential on concentrations at active sites may play an important role in drug interactions.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Gating Kinetics of Single Large-Conductance Ca2+-Activated K+ Channels in High Ca2+ Suggest a Two-Tiered Allosteric Gating Mechanism.
B. S. Rothberg and K. L. Magleby (1999)
J. Gen. Physiol. 114, 93-124
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