Calcium-activated potassium current in single Novikoff cell.
The electrophysiological properties of the hemichannels of the gap junction in a single Novikoff cell was studied using patch-clamp whole-cell recording techniques. During the experiments, a transient outward current (peak current, Ip) was found to be evoked by the increment of depolarized pulses. Ip was voltage-dependent and could be inhibited partly by CsCl and tetraethylammonium (TEA), but was blocked completely by quinidine. When the intracellular free Ca2+ concentration ([Ca2+]i) was increased, the amplitude of Ip was enhanced. Adding 10 mmol/l EGTA in the pipette solution, Ip disappeared. When the cells were bathed in symmetrical high-K+ solution, Ip also completely disappeared. These results suggest that Ip is a calcium-activated potassium current, although it cannot be blocked by apamin.
Hao
X M
XM
National Laboratory of Biomembranes and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing, China.
Fu
Y
Y
Jin
H
H
Liu
T F
TF
D000818:Animals; D001030:Apamin / Q000494:pharmacology; D002460:Cell Line; D004533:Egtazic Acid / Q000494:pharmacology; D004558:Electric Stimulation; D004594:Electrophysiology; D008114:Liver Neoplasms, Experimental; D018408:Patch-Clamp Techniques; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects* / Q000502:physiology; D011802:Quinidine / Q000494:pharmacology; D019789:Tetraethylammonium / Q000494:pharmacology
D024681:Potassium Channels, Calcium-Activated; D001030:Apamin; D004533:Egtazic Acid; D019789:Tetraethylammonium; D011802:Quinidine