| Abstrakt: |
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 mgkgd; n8) or high (0.16 mgkgd; n8) dose. Saline ICV (n9) and intraperitoneal infused L-NMMA (low, n6; high dose, n6) were served as controls. Also, L-NMMA ICV (low, n6; high dose, n6) 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 andor 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. |
