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The occurrence of stable subconductance levels in Na(+)‐activated K+ channels in excised membrane patches from guinea‐pig ventricular myocytes
Author(s) -
Mistry DK,
Tripathi O,
Chapman RA
Publication year - 1996
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1996.sp003991
Subject(s) - gating , biophysics , conductance , guinea pig , myocyte , kinetics , intracellular , ion channel , potassium channel , electrophysiology , chemistry , membrane potential , biology , anatomy , microbiology and biotechnology , biochemistry , physics , endocrinology , neuroscience , receptor , condensed matter physics , quantum mechanics
Twelve short‐lived subconductance levels have been recognized in potassium channels activated by intracellular Na+ (KNa channels) in membrane patches excised from guinea‐pig ventricular myocytes. When stable recording was achieved over a prolonged period (> 30 min), sojourns of opening to one of two stable subconductance levels (approximately 30 and 70% of the main‐state level) occurred spontaneously. These periods of activity showed similar kinetics (open and closed time distributions) to those of openings to the main‐state conductance. Opening to transient sublevels was still detected during openings of the channel to the stable sublevels. These results suggest that the KNa channel has a complex oligomeric structure, in which twelve separate pores would seem to be functionally organized into either three or four domains that show a high degree of co‐operativity in their gating.