title: Autoregulation of nitric oxide-soluble guanylate cyclase-cyclic GMP signalling in mouse thoracic aorta.
abstract: 1. The sensitivity of the soluble guanylate cyclase (sGC)-cyclic guanosine-3',5'-monophosphate (cyclic GMP) system to nitric oxide (NO) was investigated in mouse aorta from wild type (WT) and NO synthase (NOS) knockout (KO) animals. 2. The NO donor, spermine-NONOate (SPER-NO) was more potent in aortas from eNOS KO mice compared to WT (pEC50 7.30+/-0.06 and 6.56+/-0.04, respectively; n=6; P<0.05). In contrast, the non-NO based sGC activator, YC-1 was equipotent in vessels from eNOS WT and KO mice. The sensitivity of aortas from nNOS and iNOS KO animals to SPER-NO was unchanged. Forskolin (an adenylate cyclase activator), was equipotent in vessels from eNOS WT and KO animals. 3. The cyclic GMP analogue, 8-Br-cGMP was equipotent in eNOS WT and KO mice (pEC50 4. 38+/-0.04 and 4.40+/-0.05, respectively; n=5; P>0.05). Zaprinast (10-5 M) a phosphodiesterase type V (PDE V) inhibitor, had no effect on the response to SPER-NO in vessels from eNOS WT or KO mice. 4. The NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 3x10-4 M) increased the potency of SPER-NO in aortas from WT mice (pEC50 6. 64+/-0.02 and 7.37+/-0.02 in the absence and presence of L-NAME, respectively; n=4; P<0.05). 5. In summary, there is increased sensitivity of vessels from eNOS KO animals to NO. Cyclic AMP-mediated dilatation is unchanged, consistent with a specific up-regulation of sGC - cyclic GMP signalling. The functional activity of cyclic GMP-dependent protein kinase (G-kinase) and PDE V was also unchanged, suggesting that sGC is the site of up-regulation. These alterations in the sensitivity of the sGC - cyclic GMP pathway might represent a mechanism for the dynamic regulation of NO bioactivity.
authors.affiliation: Wolfson Institute for Biomedical Research, University College London, The Rayne Institute, 5 University Street, London WC1E 6JJ, U.K.
authors.forename: M B
authors.initials: MB
authors.lastname: Hussain
authors.forename: A J
authors.initials: AJ
authors.lastname: Hobbs
authors.forename: R J
authors.initials: RJ
authors.lastname: MacAllister
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000502:physiology*; D005576:Colforsin / Q000494:pharmacology; D006152:Cyclic GMP / Q000502:physiology*; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D006162:Guanylate Cyclase / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology*; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000172:deficiency / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009589:Nitrogen Oxides; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011688:Purinones / Q000494:pharmacology; D013096:Spermine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D007191:Indazoles; D009589:Nitrogen Oxides; D010726:Phosphodiesterase Inhibitors; D010975:Platelet Aggregation Inhibitors; D011688:Purinones; C091861:spermine nitric oxide complex; C090937:3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D013096:Spermine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse; D010727:Phosphoric Diester Hydrolases; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; C517382:Pde5a protein, mouse; D006162:Guanylate Cyclase; C011145:zaprinast; D006152:Cyclic GMP