RUSS, U and RINGER, T and SIEMEN, D (1993) A VOLTAGE-DEPENDENT AND A VOLTAGE-INDEPENDENT POTASSIUM CHANNEL IN BROWN ADIPOCYTES OF THE RAT. BIOCHIMICA ET BIOPHYSICA ACTA, 1153 (2). pp. 249-256. ISSN 0006-3002,
Full text not available from this repository.Abstract
Single-channel recordings of a voltage-dependent potassium channel in brown adipocytes of the rat confirm recordings of macroscopic currents. Single-channel conductance (gamma) is 8 pS at degrees 20C in KF solution inside vs. a modified Ringer's solution outside. With KCl solution outside, gamma is 17 pS for outward currents and 21 pS for inward currents. The majority of the channels inactivate with a time constant around 200 ms; deactivation occurs within milliseconds. The channel is blocked by tetraethylammonium (TEA) with an inhibiting constant of 1.8 mM. The type of block is fast. Selectivity sequence for monovalent cations is K+ > Rb+ >> NH4+ >> Li+ greater than or equal to Na+ approximate to Cs+. Cs+ at the outside causes a voltage-dependent block of inward currents. This channel is remarkably similar to the delayed rectifier of the F-type in the node of Ranvier. Occasionally, an additional K+ channel was found. This channel is voltage-insensitive, not blocked by 10 mM TEA, and has not been recorded in brown adipocytes before. Physiological relevance of this channel could be the steady-state membrane potential.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | MYELINATED NERVE; FAT-CELLS; SMALL CATIONS; K-CHANNELS; MEMBRANE; BLOCK; IONS; PERMEABILITY; MECHANISMS; RESPONSES; BROWN ADIPOSE TISSUE; POTASSIUM ION CHANNEL; POTASSIUM ION CONDUCTANCE; DELAYED RECTIFIER; ION CHANNEL SELECTIVITY; TETRAETHYLAMMONIUM; (RAT) |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:42 |
| URI: | https://pred.uni-regensburg.de/id/eprint/53626 |
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