A novel hypertonicity-induced cation channel in primary cultures of human hepatocytes.
In whole-cell recordings on primary cultures of human hepatocytes, we observe the hypertonic activation of a novel type of cation channel with a permeability ratio for Na(+):Li(+):K(+):Cs(+):NMDG(+) of 1:1.2:1.3:1.2:0.6. With a P(Ca)/P(Na) of 0.7 the channel is also clearly permeable to Ca(++). Most likely, the channel is Cl(-) impermeable but its activity critically depends on the extracellular Cl(-) concentration (with the half maximal effect at 88 mmol/l). With a 64% inhibition by amiloride and a complete block by flufenamate and Gd(3+) (at 100 micromol/l each), the channel may represent a molecular link between the amiloride-sensitive and insensitive channels reported so far.
Li
Tongju
T
Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
ter Veld
Frank
F
Nürnberger
Hartwig R
HR
Wehner
Frank
F
D002478:Cells, Cultured; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D009994:Osmolar Concentration
D007473:Ion Channels