cGMP MANP (M-atrial natriuretic peptide) is a best-in-class activator of the pGC-A (particulate guanylyl cyclase A) receptor. Furosemide increases the effectiveness of antihypertensive agents, but activates renin-angiotensin-aldosterone system. We aimed to investigate for the first time cardiorenal and neurohumoral actions of MANP in a genetic model of hypertension in spontaneously hypertensive rats. We also assessed how MANP would potentiate the blood pressure (BP)–lowering actions of furosemide while reducing the production of aldosterone.
Spontaneously hypertensive rats (N=60) were randomized in vehicle, MANP, furosemide, or MANP+furosemide groups. Furosemide (1, 5, 10 mg/kg) was given as a single bolus which in MANP+furosemide groups was followed by a 60-minute infusion of MANP.
BP was reduced in MANP300 (300 pmol/[kg·min]) and MANP600 (600 pmol/[kg·min]) groups (P<0.05) and was accompanied by significant increase in plasma cyclic guanosine monophosphate. Furosemide alone reduced BP but less compared with MANP with no change in plasma cyclic guanosine monophosphate. MANP+furosemide resulted in the greatest BP reduction and significant increase in plasma cyclic guanosine monophosphate in Fs5+MANP300, Fs10+MANP300, and Fs10+MANP600. Plasma aldosterone increased in furosemide groups, which was significantly attenuated in MANP+furosemide groups. Natriuresis and diuresis increased in all treated groups (P<0.05) with no significant differences between furosemide and furosemide+MANP. In vitro, MANP increased cyclic guanosine monophosphate level in human vascular cells.
We provide novel evidence that MANP potentiates the BP-lowering actions of furosemide, suppresses the activation of renin-angiotensin-aldosterone system, and preserves renal function. These data are highly relevant to clinical needs in the treatment of hypertension and heart failure.