Intramedullary aminoguanidine increased mean arterial pressure to 132% of control vs 121% with high sodium alone in salt-sensitive rats (P<0.05), showing iNOS blunts pressure increases.
Does selective iNOS inhibition with aminoguanidine increase arterial pressure in Dahl salt-sensitive and salt-resistant rats on high sodium intake?
Renal medullary iNOS-derived nitric oxide helps prevent excessive increases in arterial pressure during high sodium intake in Dahl salt-sensitive rats.
Absolute Event Rate: 132% vs 121%
p-value: p=< 0.05
The goal of this study was to determine the role of renal medullary inducible nitric oxide synthase (iNOS) in the arterial pressure, renal hemodynamic, and renal excretory changes that occur in Dahl/Rapp salt-resistant (R) and salt-sensitive (S) rats during high Na intake. Forty R and S rats, equipped with indwelling arterial, venous, and renal medullary catheters, were subjected to high (8%) Na intake, and selective iNOS inhibition was achieved with continuous intravenous or renal medullary interstitial infusion of aminoguanidine (AG; 3.075 mg. kg(-1). h(-1)). After 5 days of AG, mean arterial pressure increased to 132 +/- 2% control in the S rats with high Na intake and intramedullary AG compared with 121 +/- 4% control (P < 0.05) in the S rats with high Na intake alone and 121 +/- 2% control (P < 0.05) in the S rats with high Na intake and intravenous AG. AG did not change arterial pressure in R rats. AG also caused little change in renal hemodynamics, urinary Na, or H(2)O excretion or ACh-induced aortic vasorelaxation in R or S rats. The data suggest that during high Na intake, nitric oxide produced by renal medullary iNOS helps to prevent excessive increases in arterial pressure in the Dahl S rat but not the R rat.
Tian et al. (Sat,) conducted a other in Salt-sensitive hypertension (n=40). Aminoguanidine (AG) via continuous intravenous or renal medullary interstitial infusion vs. High Na intake alone was evaluated on Mean arterial pressure (% of control) (p=< 0.05). Intramedullary aminoguanidine increased mean arterial pressure to 132% of control vs 121% with high sodium alone in salt-sensitive rats (P<0.05), showing iNOS blunts pressure increases.