Hypertonic activation of a non-selective cation conductance in HeLa cells and its contribution to cell volume regulation.
In whole-cell recordings on single HeLa cells, the hypertonic activation of a cation conductance with a selectivity ratio P(Na):P(Li):P(K):P(Cs):P(NMDG):P(Ca):P(Cl) of 1.00:0.86:0.84:0.56:0.10:0.07:0.15 was observed. This (non-selective) cation conductance was reduced to 59 and 30% of maximal stimulation by Gd(3+) and flufenamate, respectively, but it was insensitive to amiloride (with each compound applied at 100 microm/l). As was determined by the Coulter counter technique, the cation conductance was the main mechanism of regulatory volume increase (RVI) in HeLa cells. Whereas a significant contribution of Na(+)/H(+) antiport was also detectable, Na(+)-K(+)-2Cl(-) symport most likely did not contribute to RVI.
Wehner
Frank
F
Department of Cell Physiology, National Institute for Physiological Sciences, 444-8585 Okazaki, Japan. frank.wehner@mpi-dortmund.mpg.de
Shimizu
Takahiro
T
Sabirov
Ravshan
R
Okada
Yasunobu
Y
D002412:Cations / Q000378:metabolism; D048429:Cell Size; D004553:Electric Conductivity; D006367:HeLa Cells; D006801:Humans; D016623:Ion Pumps / Q000378:metabolism*; D009994:Osmolar Concentration; D018408:Patch-Clamp Techniques; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism
D002412:Cations; D016623:Ion Pumps; D017923:Sodium-Hydrogen Exchangers; D028021:Sodium-Potassium-Chloride Symporters