Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.2 (guanylate cyclase)
 8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Superfusion of rat cremaster muscles with the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) elicited significant leukocyte adhesion to postcapillary venules (20- to 30-microns diameter), an effect that was attenuated by pretreatment with L-arginine (an NO precursor) or sodium nitroprusside (SNP) (an exogenous source of NO). In contrast to the effects of pretreatment, addition of SNP or L-arginine to the superfusate 30 min after the initiation of NO synthase inhibition failed to reverse the L-NAME-induced leukocyte adherence. However, this effect was reversed by administration of an anti-CD18 monoclonal antibody or 8-bromoguanosine 3',5'-cyclic monophosphate 30 min after L-NAME superfusion was initiated. These findings indicate that L-NAME promotes leukocyte adhesion to venular endothelium by a CD18-dependent mechanism in skeletal muscle and suggest that the failure of L-arginine or SNP to reverse L-NAME-induced leukocyte adherence is not due to a defect in signaling events that occur subsequent to activation of guanylate cyclase by NO derived from these agents. Because the simultaneous administration of superoxide dismutase (scavenges superoxide radicals) and SNP or L-arginine, but not superoxide dismutase alone, decreased L-NAME-induced leukocyte adherence, our results suggest that leukocyte adhesion caused by NO synthase inhibition may result in the generation of superoxide.
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PMID:Leukocyte adhesion induced by inhibition of nitric oxide production in skeletal muscle. 754 40

The endothelium-derived relaxing factor that mediates the endothelium-dependent vasodilatation first observed in 1980 has been identified as nitric oxide (NO). In addition to the endothelium, NO is formed in other cells such as neuronal cells of the brain (where it mediates synoptic plasticity), peripheral nonadrenergic noncholinergic (NANC) nerves (where it acts as an atypical neurotransmitter relaxing vascular and nonvascular smooth muscle), and various specialized epithelial cells. Other cell types such as macrophages and smooth muscle cells can be induced with bacterial endotoxin and/or cytokines to synthesize large amounts of the radical. At low concentrations, NO is an inter- and intracellular messenger molecule whose target enzyme is the soluble isoform of guanylyl cyclase. At high concentrations, the NO radical has cytostatic effects on parasitic microorganisms and tumor cells. In the vascular system, endothelium-derived NO is a physiologically significant vasodilator and inhibitor of platelet aggregation and adhesion. NANC nerve-derived NO may also contribute to vasodilatation. In addition, NO can prevent leukocyte adhesion to the endothelium by interfering with the adhesion molecule CD11/CD18, and NO has been shown to inhibit the proliferation of vascular smooth muscle cells. In sepsis and during cytokine therapy, a different NOS is induced in the vascular wall (presumably in smooth muscle cells) where it synthesizes large amounts of NO that contribute to the massive vasodilatation and shock.
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PMID:Nitric oxide synthases in the cardiovascular system. 2124 48