Blockade of nitric oxide formation inhibits the stimulation of the renin system by a low salt intake.
This study aimed to investigate the possible involvement of endothelial autacoids such as nitric oxide or prostaglandins in the well-known stimulatory effect of a low salt intake on renin secretion and renin gene expression in the kidney. To this end, plasma renin activity (PRA) and kidney renin mRNA levels were determined in male Sprague-Dawley rats fed either a normal (0.6% w/w) or a low (0.03%) NaCl diet for 10 days. To inhibit nitric oxide formation, the animals received L-nitro-argininemethylester (L-NAME, 40 mg/ kg twice a day), to inhibit prostaglandin formation the animals received meclofenamate (8 mg/kg twice a day) during the last 2 days. In animals fed a normal salt diet, L-NAME decreased PRA from 6.5 to 4.9 ng angiotensin I x h(-1) x ml(-1) and decreased renin mRNA levels by about 15%. Meclofenamate did not change PRA or renin mRNA in animals fed on normal salt diet. In vehicle-treated animals fed a low salt diet, PRA increased from 6.5 to 20.2 ng ANGI x h(-1) x ml(-1) and renin mRNA levels increased by 100%. Meclofenamate treatment did not alter these changes of PRA and renin mRNA during the intake of a low salt diet. In animals treated with L-NAME, PRA increased to only 7.2 ng ANGI x h(-1) x ml(-1) and renin mRNA increased by 20%. These findings indicate that inhibition of nitric oxide formation but not of prostaglandin formation substantially attenuates the stimulatory effect of a low salt intake on the renin system, suggesting that nitric oxide is required for this process.
Schricker
K
K
Physiologisches Institut der Universität Regensburg, Universitätsstrasse 31, D-93040 Regensburg, Germany.
Kurtz
A
A
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004039:Diet, Sodium-Restricted; D007668:Kidney / Q000378:metabolism; D008297:Male; D008469:Meclofenamic Acid / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011453:Prostaglandins / Q000096:biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000097:blood / Q000235:genetics / Q000378:metabolism*
D011448:Prostaglandin Antagonists; D011453:Prostaglandins; D012333:RNA, Messenger; D009569:Nitric Oxide; D008469:Meclofenamic Acid; D019001:Nitric Oxide Synthase; D012083:Renin; D019331:NG-Nitroarginine Methyl Ester