Activation of squid axon K+ channels. Ionic and gating current studies.
نویسندگان
چکیده
منابع مشابه
Activation of squid axon K+ channels. Ionic and gating current studies
We have used data obtained from measurements of ionic and gating currents to study the process of K+ channel activation in squid giant axons. A marked improvement in the recording of K+ channel gating currents (IKg) was obtained by total replacement of Cl- in the external solution by NO-3, which eliminates approximately 50% of the Na+ channel gating current with no effect on IKg. The midpoint o...
متن کاملGating charge movement precedes ionic current activation in hERG channels
We recently reported gating currents recorded from hERG channels expressed in mammalian TSA cells and assessed the kinetics at different voltages. We detected 2 distinct components of charge movement with the bulk of the charge being carried by a slower component. Here we compare our findings in TSA cells with recordings made from oocytes using the Cut Open Vaseline Gap clamp (COVG) and go on t...
متن کاملIonic Current Measurements in the Squid Giant Axon Membrane
The concepts, experiments, and interpretations of ionic current measurements after a step change of the squid axon membrane potential require the potential to be constant for the duration and the membrane area measured. An experimental approach to this ideal has been developed. Electrometer, operational, and control amplifiers produce the step potential between internal micropipette and externa...
متن کاملSingle Ion Occupancy and Steady-state Gating of Na Channels in Squid Giant Axon
The properties of the small fraction of tetrodotoxin (TTX)-sensitive Na channels that remain open in the steady state were studied in internally dialyzed voltage clamped squid giant axons. The observed Ussing flux ratio exponent (n') of 0.97 plus minus 0.03 (calculated from simultaneous measurements of TTX-sensitive current and (22)Na efflux) and nonindependent behavior of Na current at high in...
متن کاملInteractions of monovalent cations with sodium channels in squid axon. II. Modification of pharmacological inactivation gating
Inactivation of Na channels has been studied in voltage-clamped, internally perfused squid giant axons during changes in the ionic composition of the intracellular solution. Peak Na currents are reduced when tetramethylammonium ions (TMA+) are substituted for Cs ions internally. The reduction reflects a rapid, voltage-dependent block of a site in the channel by TMA+. The estimated fractional el...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1985
ISSN: 0022-1295,1540-7748
DOI: 10.1085/jgp.85.4.539