Pharmacological and biophysical properties of swelling-activated chloride channel in mouse cardiac myocytes.
The present study was designed to observe the properties of swelling-activated chloride channel (ICl.swell) in mouse cardiac myocytes using patch clamp techniques. In whole-cell recordings, hypotonic solution activated a chloride current that exhibited outward rectification, weak voltage-dependent inactivation, and anion selectivity with permeability sequence of I- > Br- > Cl-. The current was sensitive to Cl- channel blockers tamoxifen, NPPB and DIDS. In single-channel recordings, cell swelling activated a single channel current which showed outward rectification with open probability of 0.76 +/- 0.08 and conductance of 38.1 +/- 2.5 pS at +100 mV under [Cl-] symmetrical condition. I-V relation revealed the reversal potential as expected for a Cl(-)-selective channel. These results suggested that in mouse cardiac myocytes, swelling-activated, outward rectifying chloride channel with a single channel conductance of 38.1 +/- 2.5 pS (at +100 mV under [Cl-] symmetrical condition) underlies the volume regulatory Cl- channel.
Wang
Jun
J
Department of Physiology, Capital University of Medical Sciences, Beijing, People's Republic of China. wang_jun@cpums.edu.cn
Xu
Hongtao
H
Sun
Xiqing
X
Niu
Weizhen
W
D000818:Animals; D018118:Chloride Channels / Q000502:physiology*; D006352:Heart Ventricles / Q000166:cytology; D007038:Hypotonic Solutions; D008297:Male; D051379:Mice; D032383:Myocytes, Cardiac / Q000502:physiology*; D018408:Patch-Clamp Techniques
D018118:Chloride Channels; D007038:Hypotonic Solutions