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Single‐channel analysis of fast transient potassium currents from rat nodose neurones.
Author(s) -
Cooper E,
Shrier A
Publication year - 1985
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1985.sp015896
Subject(s) - conductance , time constant , depolarization , chemistry , potassium , potassium channel , patch clamp , electrophysiology , biophysics , physics , neuroscience , biochemistry , biology , electrical engineering , receptor , engineering , organic chemistry , condensed matter physics
Single channels that underlie the fast transient potassium current (IA) were recorded, using patch‐clamp techniques, from cultured sensory neurones. The open channel conductance was approximately 22 pS, and was constant over most of the physiological voltage range; single‐channel conductance decreased at more depolarized levels. Summing single‐channel currents resulted in an average current whose kinetics were similar to the macroscopic IA. The inactivation of these currents, at the potentials we studied, was fitted with a single exponential with a time constant of approximately 30 ms. For the currents evoked by large depolarizing steps (to +40 mV), the mean channel open time equals approximately 30 ms. For currents evoked at less depolarized levels (to 0 mV), the mean open time equals approximately 15 ms, half the inactivation time constant.