Vascular natriuretic peptide receptor-linked particulate guanylate cyclases are modulated by nitric oxide-cyclic GMP signalling

Abstract

(1) The sensitivity of the particulate guanylate cyclase-cyclic guanosine-3',5'-monophosphate (cGMP) system to atrial (ANP) and C-type (CNP) natriuretic peptides was investigated in aortae and mesenteric small arteries from wild-type (WT) and endothelial nitric oxide synthase (eNOS) knockout (KO) mice. (2) ANP and CNP produced concentration-dependent relaxations of mouse aorta that were significantly attenuated by the natriuretic peptide receptor (NPR)-A/B antagonist HS-142-1 (10(-5) M). Both ANP and CNP were more potent in aortae from eNOS KO mice compared to WT. (3) The potency of ANP and CNP in aortae from WT animals was increased in the presence of the NOS inhibitor, N(G)-nitro-L-arginine (3 x 10(-4) M) and the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolol[4,3,a]quinoxalin-1-one (5 x 10(-6) M). (4) In contrast, the potency of ANP and CNP in aortae from eNOS KO animals was reduced following pretreatment of tissues with supramaximal concentrations of the NO-donor, glyceryl trinitrate (3 x 10(-5) M, 30 min) or ANP (10(-7) M, 30 min). (5) Responses to acetylcholine in aortae from WT mice (dependent on the release of endothelium-derived NO) were significantly reduced following pretreatment of tissues with GTN (3 x 10(-5) M, 30 min) and ANP (10(-7) M, 30 min). (6) CNP and the NO-donor, spermine-NONOate caused concentration-dependent relaxations of mesenteric small arteries from WT animals that were significantly increased in eNOS KO mice compared to WT. ANP was unable to significantly relax mesenteric arteries from WT or eNOS KO animals. (7) In conclusion, both NPR-A- and NPR-B-linked pGC pathways are modulated by NO-cGMP in murine aorta and mesenteric small arteries and crossdesensitisation occurs between NPR subtypes. The biological activity of endothelium-derived NO is also influenced by the ambient concentration of NO and natriuretic peptides. Such an autoregulatory pathway may represent an important physiological homeostatic mechanism and link the paracrine activity of NO and CNP with the endocrine functions of ANP and BNP in the regulation of vascular tone and blood pressure.

Figure 1

Concentration–response curves to ANP (upper panel), CNP (middle panel) and cANF^4–23 (lower panel) in aortic rings from WT animals in the presence and absence of the NPR-A/NPR-B antagonist HS-142-1 (10⁻⁵ M). Relaxation is expressed as mean±s.e.m. percentage reversal of PE-induced tone. P<0.05, control versus HS-142-1 for ANP and CNP only (n=8).

Figure 2

Concentration–response curves to ANP (upper panel) and CNP (lower panel) in aortic rings from WT and eNOS KO animals. Relaxation is expressed as mean±s.e.m. percentage reversal of PE-induced tone. P<0.05, WT versus eNOS KO for both (n=8).

Figure 3

Concentration–response curves to ANP in aortic rings from WT animals in the presence and absence of the NOS inhibitor L-NAME (3 × 10⁻⁴ M; upper panel) or sGC inhibitor ODQ (5 × 10⁻⁶ M; lower panel). Relaxation is expressed as mean±s.e.m. percentage reversal of PE-induced tone. P<0.05, control versus L-NAME or ODQ (n⩾5).

Figure 4

Concentration–response curves to CNP in aortic rings from WT animals in the presence and absence of the NOS inhibitor L-NAME (3 × 10⁻⁴ M; upper panel) or sGC inhibitor ODQ (5 × 10⁻⁶ M; lower panel). Relaxation is expressed as mean±s.e.m. percentage reversal of PE-induced tone. P<0.05, control versus L-NAME or ODQ (n⩾5).

Figure 5

Concentration–response curves to ANP (upper panel) and CNP (lower panel) in aortic rings from eNOS KO animals in the presence and absence of GTN pretreatment (3 × 10⁻⁵ M; 30 min). Relaxation is expressed as mean±s.e.m. percentage reversal of PE-induced tone. P<0.05, control versus GTN pretreatment for both (n⩾7).

Figure 6

Concentration–response curves to ACh in aortic rings from WT animals in the presence and absence of GTN (3 × 10⁻⁵ M; 30 min; upper panel) or ANP (10⁻⁷ M; 30 min; lower panel) pretreatment. Relaxation is expressed as mean±s.e.m. percentage reversal of PE-induced tone. P<0.05, control versus GTN or ANP pretreatment (n⩾5).

Figure 7

Concentration–response curves to SPER-NO (upper panel), ANP (middle panel) and CNP (lower panel) in aortic rings from eNOS KO animals in the presence and absence of ANP pretreatment (10⁻⁷ M; 30 min). Relaxation is expressed as mean±s.e.m. percentage reversal of PE-induced tone. P<0.05, control versus ANP pretreatment for each (n⩾7).

Figure 8

Concentration–response curves to SPER-NO (upper panel), ANP (middle panel) and CNP (lower panel) in mesenteric resistance arteries from WT and eNOS KO animals. Relaxation is expressed as mean±s.e.m. percentage reversal of U46619-induced tone. P<0.05, WT versus eNOS KO for SPER-NO and CNP (n⩾4).