C-type natriuretic peptide effects on vascular reactivity in hypertension. Participation of nitric oxide system

COSTA MARÍA DE LOS ÁNGELES; CANIFFI CAROLINA; SUAREZ DI SALVO DAIANA; MENDES GARRIDO FACUNDO; CERNIELLO MICAELA; ARRANZ CRISTINA

Milán

Congreso; 21st European Meeting of Hypertension.; 2011

European Society of Hypertension.

In previous studies we demonstrated that C-type natriuretic peptide (CNP) acute infusion reduces blood pressure and increases nitric oxide (NO) synthase (NOS) activity in spontaneously hypertensive rats (SHR). The aim was to study the participation of NO in the mechanisms involved in vascular relaxation induced by CNP in SHR. Methods: Aorta thoracic segments of 3-5 mm from Wistar (W) and SHR, were suspended in Krebs solution at 37ºC and gassed (95% O2 - 5% CO2, pH:7,4). The 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, 10-8-10-5 M), CNP (10-11-10-6 M) and L-NAME (NOS inhibitor, 10-5 M). Endothelium integrity was verified with cethylcholine (ACh, 10-10-10-5 M). Aortic NOS activity (pmol 14C L-citrulline/g tissue.min) was determined. Results: Basal NOS activity was higher in SHR and CNP increased this activity in both groups (W Basal: 208±12; W CNP: 311±10*; SHR Basal: 366±21*; SHR CNP: 429±25#). The increase of NOS activity induced by CNP in SHR was lower compared with W (W ∆(CNP-Basal):103±11; SHR ∆(CNP-Basal):65±7^). *p