Zhang X, Guo Y, Dong Z, Yang Z, Zhang W
Department of Otolaryngology, PLA General Hospital, Beijing 100853, China.
Chin Med J (Engl). 2001 Mar;114(3):313-6.
To study the electrophysiological properties of sodium channels in the apical membrane of human nasal epithelial cells.
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.
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 PNa/PK 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. Ca2+ 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.
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 Ca2+ and the open probability followed a voltage-independent manner.
