C-type natriuretic peptide treatment and cardiovascular function in spontaneously hypertensive rats.

COSTA MARIA DE LOS ANGELES; CANIFFI CAROLINA; CERNIELLO MICAELA; ROMERO MARIANA; SUEIRO LAURA; RADIONOVAS VANESA; ARRANZ CRISTINA

Boston

Congreso; Experimental Biology 2013; 2013

American Physiological Society

The aim was to evaluate the effects of C-type natriuretic peptide (CNP) on systolic blood pressure (SBP), cardiac and vascular function, and nitric oxide synthase (NOS) activity on cardiac left ventricle (LV) and aorta artery (AA), in spontaneously hypertensive rats (SHR). Methods: 12 weeks-old male SHR were infused (14 days, osmotic pumps) with CNP (0,75 µg/hr.rat) or saline (S). SBP (mmHg) was recorded and echocardiography was performed. Animals were decapitated and NOS activity (pmol 14C L-citrulline/g.tissue. min) was measured in AA and LV. Vascular reactivity in AA was studied, evaluating maximal response to phenylephrine (Rmax) and concentration of acetylcholine (expressed as negative log molar) producing 50% of maximum relaxation (pEC50). Statistics: t-test.   S CNP SBP 175±3 159±5* Heart rate (bpm) 435±10 434±15 End-diastolic volume (ml) 0,16±0,02 0,23±0,03* End-systolic volume (ml) 0,05±0,02 0,07±0,03 Stroke volume (ml/min) 0,11±0,01 0,16±0,02* Cardiac output (ml) 47,8±2,0 68,8±7,4* Ejection fraction % 69±6 71±6 Fractional shortening % 34±5 35±4 NOS LV 255±5 371±8* NOS AA 117±16 202±4* Rmax 1,01±0,16 0,46±0.06* pEC50 7,4±0,1 9,3±0.2* Values are means ± SEM. *p<0.05 vs S; n=6 rats/group. Conclusion: Chronic treatment with CNP decreased blood pressure, activating cardiovascular NOS, improving cardiac efficiency and vascular function, in this model of hypertension. Supported by: UBA-Conicet.