Document Detail

Density of perfused capillaries in living human brain during functional activation.
MedLine Citation:
PMID:  1410406     Owner:  NLM     Status:  MEDLINE    
Recent evidence has indicated that functional activation of cerebral cortex is accompanied by increases of blood flow and glucose consumption but not oxygen consumption. No explanation has been advanced for this change of the flow-metabolism couple. We formulated the hypothesis that oxygen delivery to brain tissue is diffusion-limited by the enormous hemoglobin binding, and rate-limiting for the oxygen consumption of the tissue. One prediction of this hypothesis is very low oxygen tensions in the tissue. A second prediction is the inability of oxygen consumption to increase during functional activation in the absence of recruitment of capillaries for the oxygen diffusion capacity. We designed a study to test the latter prediction by calculating the density of functioning capillaries during vibrotactile stimulation of the parietal cortex. We defined functioning capillaries as capillaries that transport glucose and therefore calculated the capillary density from the glucose diffusion capacity (K1) of the cerebral capillaries. We confirmed the presence of a partial flow-CMRglc couple (2:1) during the functional activation. Oxygen consumption did not change despite an increase of capillary density in proportion to the change of blood flow.
H Kuwabara; S Ohta; P Brust; E Meyer; A Gjedde
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Progress in brain research     Volume:  91     ISSN:  0079-6123     ISO Abbreviation:  Prog. Brain Res.     Publication Date:  1992  
Date Detail:
Created Date:  1992-11-25     Completed Date:  1992-11-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376441     Medline TA:  Prog Brain Res     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  209-15     Citation Subset:  IM    
Positron Imaging Laboratories, McConnell Brain Imaging Centre, Montreal Neurological Institute, Quebec, Canada.
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MeSH Terms
Brain / metabolism*,  radionuclide imaging
Cerebrovascular Circulation*
Deoxyglucose / analogs & derivatives,  metabolism
Fluorodeoxyglucose F18
Models, Cardiovascular
Models, Neurological
Oxygen Consumption
Reference Values
Tomography, Emission-Computed / methods
Reg. No./Substance:
154-17-6/Deoxyglucose; 63503-12-8/Fluorodeoxyglucose F18

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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