Cellular localization, membrane distribution, and possible function of guanylyl cyclases A and 1 in collecting ducts of rat.
BACKGROUND
Natriuretic peptides regulate Na+ and H(2)O 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 pH(i) 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 pH(i) recovery after acidification by 30 +/- 6% (n=12), 37 +/- 7% (n=8), and 19 +/- 3% (n=8), respectively.


CONCLUSIONS
GC-A is located in the luminal membrane of IC of rat CCD and ANP acts through this receptor when regulating pH(i) 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.
Hirsch
J R
JR
Westfälische Wilhelms-Universität Münster, Medizinische Poliklinik, Experimentelle Nephrologie, Domagkstr. 3a, D-48149, Münster, Germany. hirschi@uni-muenster.de
Kruhøffer
M
M
Adermann
K
K
Heitland
A
A
Maronde
E
E
Meyer
M
M
Forssmann
W G
WG
Herter
P
P
Plenz
G
G
Schlatter
E
E
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D004232:Diuretics / Q000494:pharmacology; D005260:Female; D015870:Gene Expression; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007685:Kidney Tubules, Collecting / Q000201:enzymology / Q000502:physiology*; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D017461:Receptors, Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D004232:Diuretics; D010446:Peptide Fragments; D012333:RNA, Messenger; C056452:Ularitide; D009320:Atrial Natriuretic Factor; D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor; C091715:atrial natriuretic factor receptor A