Biophysical properties and metabolic regulation of a TASK-like potassium channel in rat carotid body type 1 cells.

Journal article

The single channel properties of TASK-like oxygen-sensitive potassium channels were studied in rat carotid body type 1 cells. We observed channels with rapid bursting kinetics, active at resting membrane potentials. These channels were highly potassium selective with a slope conductance of 14-16 pS, values similar to those reported for TASK-1. In the absence of extracellular divalent cations, however, single channel conductance increased to 28 pS in a manner similar to that reported for TASK-3. After patch excision, channel activity ran down rapidly. Channel activity in inside-out patches was markedly increased by 2 and 5 mM ATP and by 2 mM ADP but not by 100 microM ADP or 1 mM AMP. In cell-attached patches, both cyanide and 2,4-dinitrophenol strongly inhibited channel activity. We conclude that 1) whilst the properties of this channel are consistent with it being a TASK-like potassium channel they do not precisely conform to those of either TASK-1 or TASK-3, 2) channel activity is highly dependent on cytosolic factors including ATP, and 3) changes in energy metabolism may play a role in regulating the activity of these background K+ channels.

Authors: Williams, B; Buckler, K

• Publication status: Published
• Journal: American journal of physiology. Lung cellular and molecular physiology
• Volume: 286
• Issue: 1
• Pages: L221-L230
• Publication date: 2004-01-01
• DOI: 10.1152/ajplung.00010.2003
• EISSN: 1522-1504
• ISSN: 1040-0605
• Language: English
• Keywords: Carotid Body; Kinetics; Biophysical Phenomena; NAD; Membrane Potentials; Tetraethylammonium; Nerve Tissue Proteins; Patch-Clamp Techniques; Potassium Channels; Potassium Channels, Tandem Pore Domain; Cations, Divalent; Ion Channel Gating; Biophysics; Magnesium; Potassium Channel Blockers; Adenosine Triphosphate; Animals; Rats; 4-Aminopyridine