© 2001 by European Society of Cardiology
Copyright © 2000, European Society of Cardiology
Cellular localization, membrane distribution, and possible function of guanylyl cyclases A and 1 in collecting ducts of rat
aWestfälische Wilhelms-Universität Münster, Medizinische Poliklinik, Experimentelle Nephrologie, Domagkstr. 3a, D-48149 Münster, Germany
bDepartment of Clinical Biochemistry, Aarhus University Hospital, Skejby, DK-8200 Aarhus N, Denmark
cNiedersächsisches Institut für Peptid-Forschung, Feodor-Lynen-Str. 31, D-30625 Hannover, Germany
dMax-Planck-Institut für Molekulare Physiologie, Rheinlanddamm 201, D-44139 Dortmund, Germany
eWestfälische Wilhelms-Universität Münster, Institut für Arterioskleroseforschung, Domagkstr. 3, D-48149 Münster, Germany
* Corresponding author. Tel.: +49-251-83-56982; fax: +49-251-83-56973 hirschi{at}uni-muenster.de
Background: Natriuretic peptides regulate Na+ and H2O transport in the cortical collecting duct (CCD). We have shown that natriuretic peptides have no effect on ion conductances or water transport of principal cells (PC) even though a cGMP-regulated K+ channel is located in the basolateral membrane of these cells. Methods: RT-PCR was used to screen for different guanylyl cyclases (GC) in CCD and to look for the expression of GC-1 and GC-A mRNA in CCD of male and female Wistar and Sprague–Dawley rats. Polyclonal antibodies were raised against the detected GC. BCECF was used to investigate the effects of ANP on intracellular pH in intercalated cells (IC). Results: GC-A and GC-1 were detected. GC-A was immunolocalized in the luminal membrane of IC while GC-1 was mainly found in the luminal membrane of PC. GC-1 is expressed in Sprague–Dawley and Wistar rats except for male Sprague–Dawley rats, while GC-A is expressed in all strains. ANP (160 nM, n=11), urodilatin (140 nM, n=6), which had no effect in PC, significantly decreased pHi by 0.02±0.01 and 0.03±0.01 Units in IC, respectively. ANP as well as urodilatin and 8-Br-cGMP decreased the pHi recovery after acidification by 30±6% (n=12), 37±7% (n=8), and 19±3% (n=8), respectively. Conclusion: GC-A is located in the luminal membrane of IC of rat CCD and ANP acts through this receptor when regulating pHi via an inhibition of the Na+/H+-exchanger. PC do not possess GC-A. GC-1 seems to be the only GC in these cells of most rat strains tested and therefore, it could be responsible for the regulation of K+ channels in the basolateral membrane via cGMP-dependent protein kinase.
KEYWORDS Antihypertensive/diuretic agents; Hormones; Ion transport; Na/H-exchanger; Natriuretic peptide; Receptors; Signal transduction; Renal function