Role of natriuretic peptide receptors NPR-B and NPR-C in vascular tone regulation induced by C-type natriuretic peptide: Differences between normotensive and hypertensive animals

MAFKA, MAILÉN; TOMAT, ANALÍA; ARRANZ, CRISTINA; RIPARI, FRANCO; GOBETTO, NATALIA; ALCOBER, LUCÍA; ALADRO, MANUELA; CANIFFI, CAROLINA

Buenos Aires

Congreso; III International Congress in Translational Medicine. International Master Program in Biomedical Sciences; 2016

Universidad de Buenos Aires y University of Friburg

C-type natriuretic peptide (CNP) has vasodilating effect, acting through its two receptors, NPR-B and NPR-C. The aim was to evaluate the effect of CNP on and peripheral vascular resistance and conductance vascular tone in spontaneously hypertensive rats (SHR).Materials and Methods: Protocol 1: Wistar (W) and SHR (14-weeks old) were anesthetized with urethane (1 g / kg i.p.). We performed a tracheotomy and carotid artery was cannulated to record MAP (mmHg). The hind limb blood flow (HBF) was measured by an ultrasound probe that was placed surrounding the abdominal aorta (1-2 mm from the iliac bifurcation). Right common iliac artery near the bifurcation was cannulated to allow direct infusion into the circulation of left hind limb. After the stabilization period (10 min) with saline (S, 50 uL/min), the response to the administration of a bolus of CNP (1 umol/L) or the NPR-C selective agonist (cANP(4-23), 10 nmol/L) was measured. Selected doses induced no changes in MAP. H vascular resistance (HVR) was calculated as MAP/HBF. Protocol 2: Aorta thoracic segments (3-5 mm) from W and SHR, were suspended in Krebs solution (37ºC, 95% O2, 5% CO2, pH:7.4) and were allowed to equilibrate (60 min) at 1 g of basal tension. Isometric tension was recorded by a force-transducer, in preconstricted rings with phenylephrine, in presence of: CNP (10pmol/L-1umol/L) or cANP(4-23) (1 fmol/L-1nmol/L). Statistis: ANOVA two factors, Bonferroni posttest, n=6/group.Results: Results are expressed as mean±SEM. SHR presented higher MAP (Wistar=68±2 vs. SHR=91±2* *p