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dc.contributor.authorDobson, James G. Jr.
dc.contributor.authorFenton, Richard A.
dc.date2022-08-11T08:10:16.000
dc.date.accessioned2022-08-23T17:02:00Z
dc.date.available2022-08-23T17:02:00Z
dc.date.issued1993-08-01
dc.date.submitted2008-06-09
dc.identifier.citationAm J Physiol. 1993 Aug;265(2 Pt 2):H494-503.
dc.identifier.issn0002-9513 (Print)
dc.identifier.pmid8103639
dc.identifier.urihttp://hdl.handle.net/20.500.14038/44128
dc.description.abstractBecause adenosine has an antiadrenergic action in the heart, young (3-4 mo) and aged (18-20 mo) adult Sprague-Dawley and Fischer 344 rat hearts were perfused to determine whether interstitial adenosine plays a role in the reduced metabolic and mechanical responsiveness of the aged heart to beta-adrenergic stimulation. Interstitial adenosine was approximately twofold greater in aged hearts compared with young adult hearts, and 10(-8) M isoproterenol (ISO) further increased these levels. ISO increased myocardial adenosine 3',5'-cyclic monophosphate content, glycogen phosphorylase activity, and cardiac contractility by 83, 150, and 130%, respectively, in young hearts but only increased these variables by 45, 74, and 61%, respectively, in aged hearts. Sulfophenyl-theophylline prevented the reduced ISO-induced responsiveness of the above variables in aged hearts. Exogenously administered adenosine deaminase eliminated the reduced ISO-induced contractile responsiveness in aged hearts. The apparent activities of 5'-nucleotidase and adenosine deaminase were not significantly different in ventricular samples from young and aged hearts. These results suggest that the elevated interstitial level of adenosine exerts a greater antiadrenergic effect in the aged heart, rendering it less responsive to beta-adrenergic stimulation. The increased interstitial level of adenosine in the aged heart does not appear to be due to a difference in the activities of either 5'-nucleotidase or adenosine deaminase.
dc.language.isoen_US
dc.relation<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8103639&dopt=Abstract ">Link to article in PubMed</a>
dc.relation.urlhttp://ajpheart.physiology.org/content/265/2/H494.long
dc.subject5'-Nucleotidase
dc.subjectAdenosine
dc.subjectAdenosine Deaminase
dc.subjectAdrenergic beta-Antagonists
dc.subjectAging
dc.subjectAnimals
dc.subjectCoronary Vessels
dc.subjectCyclic AMP
dc.subjectExtracellular Space
dc.subjectHeart
dc.subjectInosine
dc.subjectMale
dc.subjectMyocardial Contraction
dc.subjectMyocardium
dc.subjectOxygen Consumption
dc.subjectPhosphorylases
dc.subjectRats
dc.subjectRats, Inbred F344
dc.subjectRats, Sprague-Dawley
dc.subjectCardiovascular Diseases
dc.subjectPhysiology
dc.titleAdenosine inhibition of beta-adrenergic induced responses in aged hearts
dc.typeJournal Article
dc.source.journaltitleThe American journal of physiology
dc.source.volume265
dc.source.issue2 Pt 2
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/physio_pp/10
dc.identifier.contextkey521862
html.description.abstract<p>Because adenosine has an antiadrenergic action in the heart, young (3-4 mo) and aged (18-20 mo) adult Sprague-Dawley and Fischer 344 rat hearts were perfused to determine whether interstitial adenosine plays a role in the reduced metabolic and mechanical responsiveness of the aged heart to beta-adrenergic stimulation. Interstitial adenosine was approximately twofold greater in aged hearts compared with young adult hearts, and 10(-8) M isoproterenol (ISO) further increased these levels. ISO increased myocardial adenosine 3',5'-cyclic monophosphate content, glycogen phosphorylase activity, and cardiac contractility by 83, 150, and 130%, respectively, in young hearts but only increased these variables by 45, 74, and 61%, respectively, in aged hearts. Sulfophenyl-theophylline prevented the reduced ISO-induced responsiveness of the above variables in aged hearts. Exogenously administered adenosine deaminase eliminated the reduced ISO-induced contractile responsiveness in aged hearts. The apparent activities of 5'-nucleotidase and adenosine deaminase were not significantly different in ventricular samples from young and aged hearts. These results suggest that the elevated interstitial level of adenosine exerts a greater antiadrenergic effect in the aged heart, rendering it less responsive to beta-adrenergic stimulation. The increased interstitial level of adenosine in the aged heart does not appear to be due to a difference in the activities of either 5'-nucleotidase or adenosine deaminase.</p>
dc.identifier.submissionpathphysio_pp/10
dc.contributor.departmentDepartment of Physiology
dc.source.pagesH494-503


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