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 μmol/l each), the channel may represent a molecular link between the amiloride‐sensitive and insensitive channels reported so far.