A cell shrinkage-induced non-selective cation conductance with a novel pharmacology in Ehrlich-Lettre-ascites tumour cells.
In whole-cell recordings on Ehrlich-Lettre-ascites tumour (ELA) cells, the shrinkage-induced activation of a cation conductance with a selectivity ratio P(Na):P(Li):P(K):P(choline):P(NMDG) of 1.00:0.97:0.88:0.03:0.01 was observed. In order of potency, this conductance was blocked by Gd(3+)=benzamil>amiloride>ethyl-isopropyl-amiloride (EIPA). In patch-clamp studies using the cell-attached configuration, a 14 pS channel became detectable that was reversibly activated upon hypertonic cell shrinkage. It is concluded that ELA cells express a shrinkage-induced cation channel that may reflect a molecular link between amiloride-sensitive and -insensitive channels. In addition, because of its pharmacological profile, it may possibly be related to epithelial Na+ channels (ENaCs).
Lawonn
Peter
P
Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany.
Hoffmann
Else K
EK
Hougaard
Charlotte
C
Wehner
Frank
F
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D002412:Cations; D048429:Cell Size; D004553:Electric Conductivity; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D014407:Tumor Cells, Cultured
D002412:Cations; D007473:Ion Channels