Sodium channels in the apical membrane of human nasal epithelial cells

Objective To study the electrophysiological properties of sodium channels in the apical membrane of human nasal epithelial cells Method Nasal epithelial cells of human inferior turbinate from patients with obstructive sleep apnea syndrome were cultured in serum free medium on collagen gel coated membranes at an air liquid interface and studied by a patch clamp technique Results In cell attached patches, a typical single channel current with a conductance of 21 09?pS and reversal potential of -50 96 were recorded The permeability ratio P Na /P K was more than 5 80 In the presence of 10 4 mmol/L amiloride in the pipette, the incidence of sodium channels decreased from 26 67% to 5 13% This revealed that a population of channels were inhibited by amiloride at a dose of 10 4 mmol/L Ca 2+ at dose of 10 3 mmol/L did not influence the incidence of sodium channels There was no obvious association between voltage and the open probability of the channels Conclusions Our results indicate that most Na + channels in cell attached patches of human nasal epithelial cells are amiloride sensitive and Na + selective Only a few channels are amiloride insensitive The channels were not activated by extracellular Ca 2+ and the open probability followed a voltage independent manner