Document Detail


Enhanced heme oxygenase-mediated coronary vasodilation in Dahl salt-sensitive hypertension.
MedLine Citation:
PMID:  14700508     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Cardiovascular tissues express heme oxygenase (HO), which metabolizes heme to form carbon monoxide (CO). Carbon monoxide promotes relaxation of coronary vascular smooth muscle. Increased HO-1 expression provides cardioprotection during certain pathologic conditions. On a high salt (HS) diet Dahl salt-sensitive (DS) rats develop hypertension that is accompanied by left ventricular hypertrophy, whereas Dahl salt-resistant rats (DR) do not. This study tests the hypothesis that cardiac HO-1 expression is increased in DS rats with salt-induced hypertension and provides cardioprotection by promoting coronary vasodilation. METHODS: Male DS and DR rats were placed on a HS (8% NaCl) or low salt (LS, 0.3% NaCl) diet for 4 weeks. Cardiac HO isoform expression were determined by immunohistochemistry. Experiments used isolated paced Langendorff-hearts perfused at a constant flow. Changes in coronary perfusion pressure and left ventricular contractility (dP/dt(max)) were measured in response to an inhibitor of HO, chromium mesoporphyrin (CrMP). RESULTS: With respect to the LS group, DS rats on HS diet showed elevated mean arterial pressure and increased heart weight. Coronary arterial HO-1 immunostaining was enhanced in HS rats, but HO-2 staining was similar in both groups. In isolated Langendorff-hearts the HO inhibitor CrMP increased coronary perfusion pressure and calculated coronary resistance, and decreased left ventricular contractility (dP/dt(max)) in both groups, but the response was exaggerated in HS rat hearts. In the DR strain, HS diet did not augment CrMP responses and had no effect on any of the parameters measured with respect to the LS diet. CONCLUSIONS: These findings suggest that coronary HO-1 expression is increased to promote enhanced coronary vasodilation in DS rats with salt-induced hypertension.
Authors:
Robert A Johnson; Federico J Teran; William Durante; Kelly J Peyton; Fruzsina K Johnson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of hypertension     Volume:  17     ISSN:  0895-7061     ISO Abbreviation:  Am. J. Hypertens.     Publication Date:  2004 Jan 
Date Detail:
Created Date:  2003-12-31     Completed Date:  2004-08-12     Revised Date:  2009-02-24    
Medline Journal Info:
Nlm Unique ID:  8803676     Medline TA:  Am J Hypertens     Country:  United States    
Other Details:
Languages:  eng     Pagination:  25-30     Citation Subset:  IM    
Affiliation:
Department of Physiology, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA. RobertJ393@aol.com
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MeSH Terms
Descriptor/Qualifier:
Animals
Coronary Circulation / physiology*
Disease Models, Animal
Heart Rate
Heme Oxygenase (Decyclizing) / metabolism*
Humans
Hypertension / etiology,  physiopathology*
Immunohistochemistry
Male
Myocardium / metabolism
Rats
Rats, Inbred Dahl
Sodium, Dietary / adverse effects*
Vasodilation / physiology*
Grant Support
ID/Acronym/Agency:
P20 RR017659/RR/NCRR NIH HHS; R01 HL59976/HL/NHLBI NIH HHS; R01 HL64577/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Sodium, Dietary; EC 1.14.99.3/Heme Oxygenase (Decyclizing)

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