PT  - JOURNAL ARTICLE
AU  - E. C. Aromataris
AU  - G. Y. Rychkov
AU  - B. Bennetts
AU  - B. P. Hughes
AU  - A. H. Bretag
AU  - M. L. Roberts
TI  - Fast and Slow Gating of CLC-1: Differential Effects of 2-(4-Chlorophenoxy) Propionic Acid and Dominant Negative Mutations
AID  - 10.1124/mol.60.1.200
DP  - 2001 Jul 01
TA  - Molecular Pharmacology
PG  - 200--208
VI  - 60
IP  - 1
4099  - http://molpharm.aspetjournals.org/content/60/1/200.short
4100  - http://molpharm.aspetjournals.org/content/60/1/200.full
SO  - Mol Pharmacol2001 Jul 01; 60
AB  - Our knowledge about ClC-1 muscle chloride channel gating, previously gained from single-channel recording and noise analysis, provides a theoretical basis for further analysis of macroscopic currents. In the present study, we propose a simple method of calculation of open probabilities (P o) of fast and slow gates from the relative amplitudes of ClC-1 inward current components. With this method, we investigated the effects of 2-(4-chlorophenoxy) propionic acid (CPP), a drug known to produce myotonia in animals, and dominant negative myotonic mutations, F307S and A313T, on fast and slow gating of ClC-1. We have shown that these mutations affected theP o of the slow gate, as expected from their mode of inheritance, and that CPP predominantly affected the fast gating process. CPP's action on the fast gating of mutant channels was similar to its effect in wild-type channels. Comparison of the effects of CPP and the mutations on fast and slow gating with the effects produced by reduction of external Cl− concentration suggested that CPP and mutations exert their action by affecting the transition of the channel from its closed to open state after Cl− binding to the gating site. CPP2-(4-chlorophenoxy) propionic acidWTwild-typePoopen probabilityPCRpolymerase chain reactionHEKhuman embryonic kidney