In vivo regulation of renal expression of (pro)renin receptor by a low-sodium diet.
Effects of low salt (LS) on (pro)renin receptor (PRR) expression are not well established. We hypothesized that LS enhances renal PRR expression via the cGMP-protein kinase G (PKG) signaling pathway. Sprague-Dawley rats were fed a normal-salt (NS) or LS diet associated with intrarenal cortical administration of vehicle (V), the nitric oxide (NO) synthase inhibitor nitro-l-arginine methyl ester (l-NAME), the NO donor S-nitroso-N-acetyl-dl-penicillamine (SNAP), the cGMP analog 8-bromoguanosine (8-Br)-cGMP, the guanylyl cyclase inhibitor 1H-[1, 2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), or a PKG inhibitor (PKGi) for 6 days via osmotic minipump. We evaluated the effects of each treatment on renal interstitial fluid (RIF) levels of nitrate/nitrite and cGMP and renal PRR expression. There were no significant changes in blood pressure with any of the treatments. Urinary sodium excretion was significantly lower in rats given a LS diet. Compared with NS + V, RIF nitrate/nitrite and cGMP levels increased in LS + V rats. In NS groups, RIF nitrate/nitrite and cGMP levels did not change with l-NAME, ODQ, or PKGi and increased in response to SNAP. 8-Br-cGMP increased RIF cGMP but not RIF nitrate/nitrite. In LS groups, RIF nitrate/nitrite decreased with l-NAME and did not change with ODQ or PKGi whereas RIF cGMP decreased with l-NAME, ODQ, and PKGi. PRR mRNA and protein increased in LS + V. In NS rats, PRR mRNA and protein increased in response to 8-Br-GMP and were not affected by any of other treatments. In LS rats, PRR mRNA and protein decreased significantly in response to l-NAME, ODQ, and PKGi. We conclude that LS intake enhances renal expression of PRR via cGMP-PKG signaling pathway.
Dept. of Medicine, Univ. of Virginia Health Sciences Center, Charlottesville, VA 22908-1409, USA.
Luis C
LC
Matavelli
Jiqian
J
Huang
Helmy M
HM
Siragy
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D006152:Cyclic GMP / Q000037:antagonists & inhibitors / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004039:Diet, Sodium-Restricted; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D023421:Models, Animal; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D000093342:Prorenin Receptor
C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D004791:Enzyme Inhibitors; D010069:Oxadiazoles; D011810:Quinoxalines; D011956:Receptors, Cell Surface; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester; D000093342:Prorenin Receptor