Document Detail

Spatial heterogeneity of blood flow in the dog heart. I. Glucose uptake, free adenosine and oxidative/glycolytic enzyme activity.
MedLine Citation:
PMID:  8766004     Owner:  NLM     Status:  MEDLINE    
The spatial heterogeneity of myocardial perfusion and metabolism was studied in 11 anaesthetized dogs under resting conditions. In each heart local myocardial blood flow was assessed using the tracer microsphere technique in 256 samples (mean mass: 83.1 mg) taken from the left anterior ventricular wall. In the same samples, the following biochemical parameters were determined: accumulation of [3H]-deoxyglucose (a measure of glucose uptake), free cytosolic adenosine (S-adenosylhomocysteine accumulation technique, a measure of tissue oxygenation and a possible mediator of blood flow regulation), and the specific activities of oxidative (citrate synthase, cytochrome-c-oxidase) and glycolytic (hexokinase, phosphoglycerate kinase) enzymes. Capillary density and mitochondrial and myofibril volume densities were determined by morphometry. Myocardial perfusion in each sample (average 0.77 ml min-1 g-1) varied between 0.1 and 2.5 times the mean (coefficient of variation 0.30+/-0.02). [3H]-deoxyglucose was deposited locally in proportion to perfusion. Samples showing low flow (<0.2 ml min-1 g-1) did not exhibit increased levels of cytosolic adenosine. The specific activities of the oxidative and glycolytic enzymes, however, were uniformly distributed between low and high flow areas. Furthermore, capillary density and mitochondrial and myofibril densities were similar in high and low flow regions. The results show firstly that local glucose metabolism in the heart occurs in proportion to local blood flow, suggesting that high flow regions have a higher than average metabolic rate. Secondly, regions of low flow are not compromized by critical oxygenation and most likely have a lower than average oxygen demand and finally, the homogeneous distribution of oxidative and glycolytic enzymes, as well as the homogeneous myocardial ultrastructure, suggest that areas with high and low blood flow under resting conditions may increase their metabolic rate to similar levels when required.
M Sonntag; A Deussen; J Schultz; R Loncar; W Hort; J Schrader
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pflügers Archiv : European journal of physiology     Volume:  432     ISSN:  0031-6768     ISO Abbreviation:  Pflugers Arch.     Publication Date:  1996 Jul 
Date Detail:
Created Date:  1996-10-17     Completed Date:  1996-10-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0154720     Medline TA:  Pflugers Arch     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  439-50     Citation Subset:  IM    
Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, P.O. Box 101007, D-40001 Düsseldorf, Germany.
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MeSH Terms
Adenosine / pharmacology*
Citrate (si)-Synthase / metabolism
Coronary Circulation / physiology*
Electron Transport Complex IV / metabolism
Glucose / metabolism*
Glycolysis / drug effects,  physiology
Hexokinase / metabolism
Microcirculation / drug effects,  physiology
Mitochondria, Heart / drug effects,  enzymology
Myocardium / enzymology*
Phosphoglycerate Kinase / metabolism
Reg. No./Substance:
50-99-7/Glucose; 58-61-7/Adenosine; EC Transport Complex IV; EC (si)-Synthase; EC; EC Kinase

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