Abstract
It is known that human epithelial HeLa cells exhibit cell volume regulation after osmotic shrinkage, called the regulatory volume increase (RVI), by both mechanisms mediated by activation of hypertonicity-induced cation channels (HICC) and by parallel activation of Na+/H+ exchangers and anion exchangers. To analyse the signalling network behind the HICC activation, in the present study, we examined the effects of a variety of high-specificity blockers of signalling molecules on activation of HICC monitored by whole-cell patch-clamp recordings and on the RVI monitored by electronic cell sizing. These data suggest that HICC currents and HICC-mediated RVI involve tyrosine kinases, G-proteins, PLC, PKC and p38MAP kinase, and also they appear to depend on an intact actin cytoskeleton. In contrast, RhoA, PI 3-kinase, ERK 1/2, JNK 1/2 as well as exocytotic insertion of channels into the plasma membrane do not appear to participate in the signalling machinery. [J Physiol Sci. 2007;57 Suppl:S126]
