Document Detail

One hour of myocardial ischemia decreases the activity of the stimulatory guanine-nucleotide regulatory protein Gs.
MedLine Citation:
PMID:  2551529     Owner:  NLM     Status:  MEDLINE    
The effect of 1 hour of myocardial ischemia on the function of the stimulatory guanine-nucleotide-binding protein Gs was examined. This study follows our recent finding that myocardial ischemia increases the density of beta-adrenoreceptors in a conscious canine model while having the opposite effect on the activity of adenylate cyclase. Coronary artery occlusion was induced in five conscious dogs and verified by measurement of blood flow using the Doppler and microsphere techniques. Alterations in the level and function of Gs were examined in sarcolemmal membranes prepared from ischemic and nonischemic regions of the left ventricle. After 1 hour of coronary artery occlusion, the functional activity of sarcolemmal Gs, as determined by reconstitution with cyc- membranes, decreased by 27 +/- 7% in the ischemic zone. Cholera toxin labeling performed in parallel with the reconstitution studies demonstrated a similar decrease of 28 +/- 7%. This was associated with decreases in basal activity and decreases in adenylate cyclase activity stimulated by GTP, GTP plus isoproterenol, sodium fluoride, and forskolin. Thus, a defect distal to the beta-adrenoreceptor occurs in the transduction of adrenergic signals to the heart as a consequence of 1 hour of ischemia.
E E Susanni; W T Manders; D R Knight; D E Vatner; S F Vatner; C J Homcy
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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:  Circulation research     Volume:  65     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1989 Oct 
Date Detail:
Created Date:  1989-11-09     Completed Date:  1989-11-09     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1145-50     Citation Subset:  IM; S    
Cardiac Unit, Massachusetts General Hospital, Boston.
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MeSH Terms
Adenylate Cyclase / metabolism
Cholera Toxin / diagnostic use
Coronary Disease / enzymology,  metabolism*,  physiopathology
GTP-Binding Proteins / metabolism*
Receptors, Adrenergic, beta / metabolism
Time Factors
Grant Support
Reg. No./Substance:
0/Receptors, Adrenergic, beta; 9012-63-9/Cholera Toxin; EC 3.6.1.-/GTP-Binding Proteins; EC Cyclase

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