Cgmp-activating peptides do not regulate electrogenic electrolyte
transport in principal cells of rat ccd.
Schlatter, E., R. Cermak, W. G. Forssmann, J. Hirsch, R. Kleta, M.
Kuhn, D. Sun, and J. A. Schafer.
Westf[umlaut]alische-Wilhelms-Universit[umlaut]at M[umlaut]unster,
Medizinische Poliklinik, Experimentelle Nephrologie, 48149
M[umlaut]unster, Germany, Nieders[umlaut]achsisches Institut
f[umlaut]ur Peptid-Forschung, 30625 Hannover, Germany, University of
Alabama at Birmingham, Department of Physiology and Biophysics,
Birmingham, AL 35294-0005, USA
APStracts 3:0160F, 1996.
K+ channels in the basolateral membrane of rat cortical collecting
duct (CCD) are regulated by a cGMP-dependent protein kinase (Hirsch
& Schlatter, Pfl[umlaut]ugers Archiv. 429: 338, 1995). Conflicting
data exist on the effects of cGMP-activating agonists on Na+
transport in these cells. Thus, we tested members of the family of
peptides that activate guanylate cyclase G (CDD/ANP =
cardiodilatin/atrial natriuretic peptide, BNP, CNP, urodilatin,
guanylin, uroguanylin) as well as bradykinin +/- CDD/ANP on membrane
voltages (Vm) of principal cells of isolated rat CCD using the slow
-whole-cell patch clamp technique (Schlatter et al., Pfl[umlaut]ugers
Archiv. 421: 381, 1992). None of the agonists tested changed Vm
significantly. There was also no effect of db-cGMP on AVP-dependent
lumen-to-bath Na+ fluxes, transepithelial voltage, or osmotic water
permeability in isolated perfused rat CCD. Finally, CDD/ANP increased
intracellular cGMP only in glomeruli but not in CCD. Thus the
findings provide no evidence for control of electrogenic electrolyte
transport by these natriuretic peptides in principal cells of rat
CCD, and the agonist that physiologically regulates the cGMP
-dependent K+ channels remains to be identified.
Received 18 December 1995; accepted in final form 27 August 1996.
APS Manuscript Number F421-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996