cGMP-activating peptides do not regulate electrogenic electrolyte transport in principal cells of rat CCD
Schlatter, E.; Cermak, R.; Forssmann, W.G.; Hirsch, J.R.; Kleta, R.; Kuhn, M.; Sun, D.; Schafer, J.A.
American Journal of Physiology 271(6 Pt 2): F1158-F1165
1996
ISSN/ISBN: 0002-9513 PMID: 8997389 Document Number: 457143
K+ channels in the basolateral membrane of rat cortical collecting duct (CCD) are regulated by a cGMP-dependent protein kinase (J. Hirsch and E. Schlatter. Pfluegers Arch. 429: 338-344, 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 increase intracellular cGMP (cardiodilatin/atrial natriuretic peptide (CDD/ANP), brain natriuretic peptide, C-type natriuretic peptide, urodilatin, guanylin, and uroguanylin), as well as bradykinin +- CDD/ANP on membrane voltages (V-m) of principal cells of isolated rat CCD using the slow whole cell patch-clamp technique (E. Schlatter, U. Frobe, and R. Greger. Pfluegers Arch. 421: 381-387, 1992). None of the agonists tested changed V-m significantly. There was also no effect of dibutyryl guanosine 3',5'-cyclic monophosphate (DBcGMP) on AVP-dependent lumen-to-bath Na+ flux, 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.