Referenced in: none

Automatically associated channels: ClC4

Title: O2-sensitive K+ channels in neuroepithelial body-derived small cell carcinoma cells of the human lung.

Authors: I O'Kelly, C Peers, P J Kemp

Journal, date & volume: Am. J. Physiol., 1998 Oct , 275, L709-16

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/9755103

Abstract
Neuroepithelial bodies act as airway O2 sensors, but studies of their activity at the cellular level have been severely limited because they are present at such a low density in lung tissue. Small cell lung carcinoma (SCLC) cells are believed to be derived from neuroepithelial body cells and may represent a model system for investigating the mechanisms of airway chemoreception. Here we have used the whole cell patch-clamp technique to investigate the effects of acute hypoxia on voltage-gated ionic currents and membrane potential in H-146 SCLC cells. Step depolarizations evoked transient inward currents due to activation of Na+ and Ca2+ channels, followed by outward K+ currents. K+ currents were partially inhibited by 200 microM Cd2+ (indicative of the presence of a Ca2+-dependent component of the K+ current) and were inhibited by tetraethylammonium (TEA) in a concentration-dependent manner, although even at 100 mM TEA, a residual K+ current could be detected. Hypoxia (PO2 15-20 mmHg) caused a reversible inhibition of outward K+ currents without affecting inward currents. Inhibition by hypoxia was also observed in the presence of Cd2+. Hypoxia and TEA caused membrane depolarization in H-146 cells, and their effects appeared additive. These findings indicate that H-146 cells possess O2-sensitive, Ca2+-independent K+ channels that can influence cell membrane potential. SCLC cells may, therefore, represent a good model for investigating the mechanisms underlying O2 sensing by airway chemoreceptor cells.