Chronic treatment with C-type natriuretic peptide improves vascular function in spontaneously hypertensive rats

COSTA A.; CANIFFI C.; BOUCHET G; WENK S; SAVIGNANO L; CERNIELO M; ROMERO M; MAC LAUGHLIN M; ARRANZ C

Milán

Congreso; 23rd European Meeting of Hypertension.; 2013

European Society of Hypertension.

In previous ?in vitro? studies, we have demonstrated that endothelial nitric oxide synthase (NOS) activation mediates, almost in part, vascular relaxation induced by C-type natriuretic peptide in normotensive and hypertensive rats. The aim was to evaluate the effects of (CNP) chronic treatment on systolic blood pressure (SBP), vascular reactivity and NOS activity on aorta artery (AA), in spontaneously hypertensive rats (SHR) andWistar normotensive ones (W). Methods: 12 weeks-old male SHR andW were infused (14 days, Alzet osmotic pumps, model 1002) with CNP (0,75 µg/hr.rat) or saline (S). SBP (mmHg) was recorded. At the end of the treatment, animals were decapitated and NOS activity (pmol 14C L-citrulline/g.tissue. min) was measured in AA. To evaluate vascular reactivity, aortic rings were allowed to equilibrate for 60 min and readjusted to basal tension 1 g. Isometric tension (g) was recorded by a force-transducer, in presence of: phenylephrine (PE, 10-7-10-5 M) or acetylcholine (Ach, 10-9-10-4 M). Maximal response to PE (Rmax) and concentration of Ach (expressed as negative log molar) producing 50% of maximum relaxation (pEC50) were evaluated. Statistics: Two way ANOVA, Bonferroni post-test and t-test. Results: CNP decreased blood pressure in SHR, but the peptide did not modified this parameter inW. CNP increased vascular NOS activity in both groups, showing a lower NOS response in SHR compared with normotensive animals (difference in NOS activity CNP-S: W= 104±3 vs SHR= 84±5*,*p