EurekaMag.com logo
+ Site Statistics
References:
53,869,633
Abstracts:
29,686,251
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

Role of nitric oxide in the regulation of coronary vascular tone in hearts from hypertensive rats. Maintenance of nitric oxide-forming capacity and increased basal production of nitric oxide



Role of nitric oxide in the regulation of coronary vascular tone in hearts from hypertensive rats. Maintenance of nitric oxide-forming capacity and increased basal production of nitric oxide



Hypertension 25(2): 186-193



In arterial hypertension, coronary flow reserve, expressed by the difference between autoregulated and maximal coronary flow, is frequently impaired. Previous experimental and clinical investigations using acetylcholine as a stimulus for the production of endothelium-derived relaxing factor suggested that an impaired endothelium-dependent vasodilation, presumably caused by a decreased formation of nitric oxide (NO), may account for this microvascular dysfunction. However, so far no study has been performed that quantifies the formation of NO within the coronary circulation of hypertensive hearts to assess its role in setting coronary vascular tone in the hypertensive heart. We therefore quantified NO formation within the coronary circulation of constant flow-perfused, isolated hearts from spontaneously hypertensive rats (SHR, 16th to 26th week), as a model for hypertensive heart disease, and from the normotensive control strain (Wistar-Kyoto, WKY) using the oxyhemoglobin technique. Coronary perfusion pressure and vascular resistance were almost 30% higher in SHR compared with WKY hearts. Intracoronarily applied NO decreased coronary vascular resistance by maximally 45% of resting values in a concentration-dependent manner in both groups. The bradykinin-induced decrease in coronary vascular resistance and the parallel increase in NO release were comparable in SHR and WKY hearts and fell within the vasodilator range of exogenously applied NO. Moreover, basal release of NO normalized to heart wet weight was 50% higher in SHR compared with WKY hearts. Rates of basal NO release were correlated inversely with changes in coronary perfusion pressure and vascular resistance in both groups (r= -.85 and -.84, respectively, P lt .05). This relation between resting coronary vascular resistance and NO formation. as a critical determinant of coronary flow, was shifted significantly to higher levels in SHR. From the present data we conclude that in the coronary circulation of SHR, NO formation is preserved under basal and stimulated conditions and critically determines resting coronary resistance. Moreover, the enhanced basal release of NO may serve the purpose of compensating the higher coronary vascular resistance of hypertensive hearts.

(PDF emailed within 1 workday: $29.90)

Accession: 009368830

Download citation: RISBibTeXText

PMID: 7843768



Related references

Reduced basal nitric oxide-mediated dilatation and decreased endothelial nitric oxide synthase expression in coronary vessels of spontaneously hypertensive rats. European Heart Journal 17(ABSTR SUPPL ): 117, 1996

Increased nitric oxide production accompanied by the up-regulation of inducible nitric oxide synthase in vascular endothelium from patients with systemic lupus erythematosus. Arthritis and Rheumatism 40(10): 1810-1816, 1997

The role of nitric oxide in the pathogenesis of spontaneous murine autoimmune disease: increased nitric oxide production and nitric oxide synthase expression in MRL-lpr/lpr mice, and reduction of spontaneous glomerulonephritis and arthritis by orally administered NG-monomethyl-L-arginine. Journal of Experimental Medicine 179(2): 651-660, 1994

The role of nitric oxide in the pathogenesis of spontaneous murine autoimmune disease: increased nitric oxide production and nitric oxide synthase expression in MRL-lpr/lpr mice, and reduction of spontaneous glomerulonephritis and arthritis by orally administered NG-monomethyl-L- arginine. Journal of Experimental Medicine 179(2): 651-660, 1994

Nitric oxide synthase inhibition by haem oxygenase decreases macrophage nitric-oxide-dependent cytotoxicity: a negative feedback mechanism for the regulation of nitric oxide production. Research in Immunology 149(7-8): 741-744, 1998

Up-Regulation of Inducible Nitric Oxide Synthase and Nitric Oxide in Helicobacter pylori-Infected Human Gastric Epithelial Cells: Possible Role of Interferon- in Polarized Nitric Oxide Secretion. Helicobacter 7(2): 116-128, 2002

Up-regulation of inducible nitric oxide synthase and nitric oxide in Helicobacter pylori-infected human gastric epithelial cells: possible role of interferon-gamma in polarized nitric oxide secretion. Helicobacter 7(2): 116-128, 2002

Antioxidant enzymes suppress nitric oxide production through the inhibition of NF-kappa B activation: role of H(2)O(2) and nitric oxide in inducible nitric oxide synthase expression in macrophages. Nitric Oxide 5(5): 504-513, 2001

Acute and chronic inhibition of nitric oxide synthase in conscious rabbits: role of nitric oxide in the control of vascular tone. Journal of Cardiovascular Pharmacology 21(5): 804-814, 1993

Reduced ventromedial hypothalamic neuronal nitric oxide synthase and increased sensitivity to NOS inhibition in dietary obese rats: further evidence of a role for nitric oxide in the regulation of energy balance. Brain Research 1016(2): 222-228, 2004

Increased inflammatory activity parallels increased basal nitric oxide production and blunted response to nitric oxide in vivo in rheumatoid arthritis. Annals of the Rheumatic Diseases 62(7): 630-634, 2003

Effects of amlodipine on nitric oxide synthase mRNA expression and coronary microcirculation in prolonged nitric oxide blockade-induced hypertensive rats. Journal of Cardiovascular Pharmacology 34(2): 173-181, 1999

Vanillic acid prevents the deregulation of lipid metabolism, endothelin 1 and up regulation of endothelial nitric oxide synthase in nitric oxide deficient hypertensive rats. European Journal of Pharmacology 743: 117-125, 2015

Enhanced vascular permeability in solid tumor is mediated by nitric oxide and inhibited by both new nitric oxide scavenger and nitric oxide synthase inhibitor. Japanese Journal Of Cancer Research. 85(4): 331-334, 1994

Chronic exercise in dogs increases coronary vascular nitric oxide production and endothelial cell nitric oxide synthase gene expression. Circulation Research 74(2): 349-353, 1994