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Inhibition of Ion Transport through Gramicidin A Channels by the Addition of Local Anesthetic Procaine
Author(s) -
Yamaguchi Takuya,
Shirai Osamu,
Kitazumi Yuki,
Kano Kenji
Publication year - 2018
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201700609
Subject(s) - procaine , chemistry , permeation , cationic polymerization , gramicidin , ion channel , biophysics , membrane , chromatography , pharmacology , polymer chemistry , biochemistry , medicine , receptor , biology
The blocking effects of the cationic procaine, a typical local anesthetic (LA), on ion transport through gramicidin A (gA) channels between two aqueous phases (W1 and W2) were electrochemically elucidated. Although the gA channels promoted the permeation of monovalent cations, especially Cs + , the addition of procaine to W1 decreased the permeation of Cs + through these channels from W1 to W2. This can be explained based on the following mechanism. Hydrophobic cationic procaine tends to approach the pore of a gA channel. Since it is too large to enter the pore, it cannot pass through the channel. Thus, cationic procaine inhibits the permeation of Cs + from W1 to W2 by competing with Cs + for access to the entrances of the gA channels. It is postulated that the decrease in the apparent activity of Cs + caused by this competition prevents ion transport through the gA channels.