Expression of a hypotonic swelling-activated cl conductance during
ontogeny of the collecting duct epithelium.
Huber, Stephan M., and Michael F. Horster.
Physiologisches Institut, Ludwig-Maximilians-UniversitSt,
Pettenkoferstr. 12, 80336 M[diaeresis]ynchen, Germany
APStracts 5:0062F, 1998.
Developmental expression of ion channels possibly participating in
regulatory volume decrease was studied in rat embryonic (E17) and
perinatal (P1-6) ureteric bud, and in postnatal (P9-14) cortical
collecting duct cells in primary monolayer culture. In isotonic bath
solution whole-cell conductance (nS/10pF+/-SE) was highest in E17
(4.0+/-0.5, n=31) compared with P1-6 (2.0+/-0.1, n=16) and P9-14
(1.3+/-0.2, n= 2) due to a decreasing contribution of a DIDS
-sensitive Cl conductance, from E17 (2.8+/-0.7, n=12) to P1-6 (0.53+/
-0.07, n=9) and P9-14 (0.05+/-0.1, n=7). Cl conductance in E17
exhibited a permselectivity of I Cl Br>>gluconate and activated
time-dependently. Hypotonic bath solution induced a large increase of
whole-cell conductance in P1-6 and in P9-14 but not in E17 (by
20.0+/-3.7, 21.5+/-5.5, and 4.9+/-1.7; n=11, 12, and 25,
respectively) due to the activation of a time dependently
inactivating Cl conductance with a permselectivity of
I3Br>Cl>>gluconate. In conclusion, the expression of Cl
channels, as studied in vitro, appears to shift from an apparently
constitutively active embryonic to a hypotonic swelling-activated
type during late embryonic development of the collecting duct.
Received 3 November 1997; accepted in final form 26 February
1998.
APS Manuscript Number F345-7.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 9 March 1998