I-CLN - A CHLORIDE CHANNEL PARAMOUNT FOR CELL-VOLUME REGULATION

Cell volume regulation is a ubiquitous cell regulatory mechanism based on meticulously controlled ion transport mechanisms. Keeping the abso lute volume constant seems to be of the highest priority for most cell s and is achieved at the expense of altered intracellular ion concentr ations. We have been able to demonstrate that I-Cln, a chloride channe l cloned from epithelial cells, is paramount for the ability of swolle n cells to regulate their volume back to that under resting conditions . A unique feature of I-Cln is the distinct sensitivity bf these chann els for nucleotides and nucleoside analogues added to the extracellula r fluid. In addition, cromolyn sodium and nedocromil sodium, drugs use d by patients with asthma, are able to impede the function of these ch annels.