Chloride currents in primary cultures of rabbit proximal and distal
convoluted tubules..
Rubera, Isabelle, Michel Tauc, Michel Bidet, Chantal Poujeol,
B[acute]eatrice Cuiller, Annette Watrin, Nicolas Touret, and Philippe
Poujeol.
UMR CNRS 6548 Universit[acute]e de Nice-Sophia Antipolis, O6108
Nice Cedex 2, France
APStracts 5:0118F, 1998.
Cl- conductances were studied in cultured rabbit proximal convoluted
tubule (PCT) epithelial cells and compared with those measured in
cultured distal bright convoluted tubule (DCTb) epithelial cells.
Using the whole- cell patch clamp technique, three types of Cl-
conductances were identified in DCTb cultured cells. These consisted
of volume-sensitive, Ca2+-activated and forskolin-activated Cl-
currents. In PCT cultured cells, only volume sensitive and Ca2+
activated Cl- currents were recorded. The characteristics of Ca2+
-activated currents in PCTcells closely resembled to those in DCTb
cells. Volume-sensitive Cl- currents could be elicited both in PCT
and in DCTb cells by hypotonic stress. The pharmacological profile of
this conductance was established for both cell types. Forskolin
activated a linear Cl- current in DCTb cells but not in PCT cells.
This conductance was insensitive to DIDS and corresponds to CFTR-like
channels. Quantitative measurements of SPQ fluorescence showed that
only the apical membrane of DCTb cells possessed a Cl- pathway that
was sensitive to forskolin. RT-PCR experiments showed the presence of
CFTR mRNA in both cultures whereas immunostaining experiments
revealed the expression of CFTR in DCTb cells only. The physiological
role of the different types of channels is discussed.
Received 17 February 1998; accepted in final form 25 June 1998.
APS Manuscript Number F36-8.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 30 July 1998