Salt-sensitive hypertension in conscious rats induced by chronic nitric oxide blockade.
This study examined the effects of alterations in salt-intake on blood pressure (BP) in rats chronically treated intravenously with or without the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) (8.6 mg/kg/day). The changes in mean arterial pressure (MAP), the renal cortical and medullary blood flow (CBF and MBF), and the sodium balance were determined by implanted optical fibers and laser-Doppler flow measurement techniques in the conscious rats. The results showed that high salt intake (7.4 mEq/day) elevates CBF (139% +/- 15%), but has no significant effect on MAP or MBF in control rats; in L-NAME-treated rats, high salt intake elevates MAP, produces no change in CBF, and decreases MBF (51% +/- 14%), as well as increasing the sodium balance (0.26 +/- 0.23 mEq/day to 1.29 +/- 0.47 mEq/day). The present experiments indicated that NO appears to maintain the MBF during high salt intake and to prevent the changes in MAP, and, in the absence of NO, salt-sensitive hypertension develops. Nitric oxide plays an important role in the development of salt-sensitive hypertension with the change of MBF.
Nakanishi
Kazushige
K
Second Department of Internal Medicine, Toho University, School of Medicine, Tokyo, Japan. kazunaka@med.toho-u.ac.jp
Hara
Noriko
N
Nagai
Yohko
Y
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors; D006973:Hypertension / Q000139:chemically induced* / Q000503:physiopathology*; D007672:Kidney Cortex / Q000098:blood supply; D007679:Kidney Medulla / Q000098:blood supply; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012079:Renal Circulation / Q000187:drug effects; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D012965:Sodium Chloride; D012964:Sodium; D019331:NG-Nitroarginine Methyl Ester