AJP - Cell Physiology, Vol 263, Issue 3 C708-C713, Copyright © 1992 by American Physiological Society
Small linear chloride channels are endogenous to nonepithelial cells
S. E. Gabriel, E. M. Price, R. C. Boucher and M. J. Stutts
Department of Medicine, University of North Carolina, Chapel Hill 27599.
We used both single-channel and whole cell patch-clamp techniques to
characterize chloride channels and currents endogenous to Sf9 cells, 3T3
fibroblasts, and Chinese hamster ovary cells. In cell-attached patches from
these cell types, anion channels were observed with low ohmic conductance
(4-11 ps), linear current-voltage relationships, and little time- or
voltage-dependent behavior. These channels are very similar to the Cl-
channels reported to appear concomitant with the expression of cystic
fibrosis transmembrane conductance regulator (CFTR) in these cell lines.
The presence of such endogenous channels suggests either that low levels of
CFTR are present in all of these cell lines prior to transfection or that
an endogenous non-CFTR channel is present in these cell types. Our results
suggest that at least some of the channel behaviors attributed to
expressed, recombinant CFTR in previous studies may have been due to these
endogenous Cl- channels.
