Abstract
Cell shrinkage, called apoptotic volume decrease (AVD), is one of the characteristic early events in the apoptosis processes. On the other hand, the hypertonicity-induced cation channel (HICC) plays a highly efficient role in the regulatory volume increase (RVI) of many cell types after osmotic shrinkage. By means of electronic cell sizing and whole-cell patch-clamp techniques, in the present study, effects of HICC activation on the staurosporine (STS)-induced AVD and apoptosis were examined in HeLa cells on the basis of a differential time protocol for activation of both processes and by use of blockers of the HICC. Hypertonic stress was found to reduce STS-induced AVD, cell death, caspases 3/7 activation and DNA fragmentation, and these effects were actually due to activation of the HICC. On the other hand, treatment with STS was found to significantly diminish osmotic HICC activation. Thus, it is concluded that the HICC plays not only a volume-restoring role in osmotic shrunken cells but also a death-rescuing role in apoptotic shrunken cells. [J Physiol Sci. 2008;58 Suppl:S209]
