Aim: 

The natriuretic peptides constitute a family of three cyclic peptides, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). ANP and BNP are primarily cardiac hormones secreted mainly from atria and ventricles, respectively. CNP is produced by vascular endothelium and acts locally as a paracrine regulator of vascular tone. The aim of this study is to evaluate the pathway involved in CNP induced intracellular calcium and nitric oxide modulation in HUVECs.

Methods: 

The HUVECs were treated with CNP at 10–6M in the presence and with or without addition of L-NAME (1mM as NOS inhibitor) , SNAP (10 -4 M as NO donor) 8Br-cGMP (100 10-6M as PKG activator), Rp-8Br-Pet-cGMPs (100 10-6M as PKG inhibitor). The Ca2+ and NO are determined respectively by the labels Fluo-3AM and DAF-2DA. The data evaluation is at 3 and 6 hours. The images were captured by ProImagePlus on Olympus IX 50 microscope and their analysis was performed by NIH ImageJ program.

Results: 

The microfluorometric method reveals that CNP reduce the intracellular calcium levels via PKGI/cGMP pathway and also increases the NO levels in HUVEC, in fact, as confirmed by the effects of NO generator SNAP (10-4 M) and NOS inhibitor L-NAME (1 mM) . Further researches on the crosstalking between these regulating pathways shall ascertain and fine tune the NO molecular concentrations that effectively modulate PKGi activity.