Contribution of central nitric oxide to the regulation of blood pressure and sodium balance in DOCA-salt hypertension.
We examined whether central nitric oxide is involved in blood pressure (BP) regulation in deoxycorticosterone acetate (DOCA)-salt hypertension. DOCA-salt rats were intracerebroventricularly infused (ICV) NG-monomethyl L-arginine (L-NMMA) for 4 weeks at either low (0.08 mg/kg/d; n = 8) or high (0.16 mg/kg/d; n = 8) dose. Saline ICV (n = 9) and intraperitoneal infused L-NMMA (low, n = 6; high dose, n = 6) were served as controls. Also, L-NMMA ICV (low, n = 6; high dose, n = 6) was conducted in normal rats. At week 3 and after, DOCA-salt with low L-NMMA ICV showed a higher BP than saline ICV (at week 4: 167.4 +/- 3.6 vs. 150.3 +/- 3.9 mm Hg, P < 0.01); this difference of BP was cancelled after ganglionic block. High L-NMMA ICV did not affect the trend of BP; however, it caused a reduced amount of saline drinking and a less estimated sodium retention than saline or low L-NMMA ICV (for 3 wk; 47.5 +/- 1.1 vs. 66.0 +/- 3.7 and 61.7 +/- 2.5 mmol, P < 0.01). In normal rats, high, but not low, L-NMMA ICV elevated BP with no effect on drinking behavior. Intraperitoneal infused L-NMMA did not affect the development of hypertension and/or sodium balance. These data suggested that, in DOCA-salt, central nitric oxide is involved in BP regulation through the dual action on sympathetic nervous activity and sodium balance.
Seto
Shinji
S
Department of Cardiovascular Medicine, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan. s-seto@net.nagasaki-u.ac.jp
Nagao
Shoichi
S
Ozeki
Shin-Ichiro
S
Tetsuo
Hirokuni
H
Akahoshi
Masazumi
M
Yano
Katsusuke
K
D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D003900:Desoxycorticosterone / Q000494:pharmacology; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005730:Ganglionic Blockers / Q000494:pharmacology; D018738:Hexamethonium / Q000494:pharmacology; D006973:Hypertension / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D012083:Renin / Q000097:blood; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000008:administration & dosage; D019323:omega-N-Methylarginine / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D005730:Ganglionic Blockers; D001127:Arginine Vasopressin; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D018738:Hexamethonium; D003900:Desoxycorticosterone; D012965:Sodium Chloride; D012964:Sodium; D019001:Nitric Oxide Synthase; D012083:Renin; D009638:Norepinephrine