Salt-sensitive hypertension in conscious rats induced by chronic nitric oxide blockade

• Published in: American journal of hypertension Vol. 15; no. 2; pp. 150 - 156
• Main Authors: Nakanishi, Kazushige, Hara, Noriko, Nagai, Yohko
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.02.2002; Oxford University Press; Elsevier Science
• Subjects: Animals; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure - drug effects; Cardiology. Vascular system; Dose-Response Relationship, Drug; Enzyme Inhibitors; Experimental diseases; Hypertension - chemically induced; Hypertension - physiopathology; Kidney Cortex - blood supply; Kidney Medulla - blood supply; Male; Medical sciences; medullary blood flow; NG-Nitroarginine Methyl Ester; nitric oxide; Nitric Oxide - antagonists & inhibitors; Rats; Rats, Sprague-Dawley; Reference Values; Renal Circulation - drug effects; Salt-sensitive hypertension; Sodium - metabolism; Sodium Chloride - administration & dosage; Sodium Chloride - pharmacology; Salt-sensitive hypertension; nitric oxide; medullary blood flow; Hypertension; Regional blood flow; Rat; Pathogenesis; Rodentia; Cardiovascular disease; Kidney; Vertebrata; Sensitivity; Mammalia; Sodium; Follow up study; Animal; Nitric oxide
• ISSN: 0895-7061; 1879-1905; 1941-7225
• DOI: 10.1016/S0895-7061(01)02267-1

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.