Tetraethylammonium-sensitive calcium-sensitive potassium current in a subclass of the bullfrog dorsal root ganglion cells.
Bullfrog dorsal root ganglion (DRG) cells were classified into three types, As, Ar and C, according to their electrophysiological properties. Actions of tetraethylammonium (TEA; 100 microM-100 mM) on As-type cells were examined using current- and voltage-clamp methods; TEA caused a membrane depolarization or an inward current, associated with a decrease in membrane conductance. These TEA-induced responses reversed in polarity at -85 to -90 mV, and the change in reversal potential followed the Nemst equation as extracellular K+ concentration was changed. The TEA-induced responses were reversibly inhibited by Ca(+2)-free/high-Mg+2 solutions and inorganic Ca blockers. It is concluded that bullfrog DRG As-type cells might be also endowed with Ca-sensitive K channels which may be open at rest and blocked by TEA.
Department of Autonomic Physiology, Tokyo Medical and Dental University, Japan.
K
K
Morita
Y
Y
Katayama
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D005260:Female; D005727:Ganglia, Spinal / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*; D011893:Rana esculenta; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology*
D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D019789:Tetraethylammonium; D002118:Calcium