Linked Life Data

17626829

Source:http://linkedlifedata.com/resource/pubmed/id/17626829

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2007-10-5
pubmed:abstractText
To investigate the dynamics of tissue oxygen demand and supply during brain functions, we simultaneously recorded Po(2) and local cerebral blood flow (LCBF) with an oxygen microelectrode and laser Doppler flowmetry, respectively, in rat somatosensory cortex. Electrical hindlimb stimuli were applied for 1, 2, and 5 s to vary the duration of evoked cerebral metabolic rate of oxygen (CMR(O(2))). The electrical stimulation induced a robust increase in Po(2) (4-9 Torr at peak) after an increase in LCBF (14-26% at peak). A consistent lag of approximately 1.2 s (0.6-2.3 s for individual animals) in the Po(2) relative to LCBF was found, irrespective of stimulus length. It is argued that the lag in Po(2) was predominantly caused by the time required for oxygen to diffuse through tissue. During brain functions, the supply of fresh oxygen further lagged because of the latency of LCBF onset ( approximately 0.4 s). The results indicate that the tissue oxygen supports excess demand until the arrival of fresh oxygen. However, a large drop in Po(2) was not observed, indicating that the evoked neural activity demands little extra oxygen or that the time course of excess demand is as slow as the increase in supply. Thus the dynamics of Po(2) during brain functions predominantly depend on the time course of LCBF. Possible factors influencing the lag between demand and supply are discussed, including vascular spacing, reactivity of the vessels, and diffusivity of oxygen.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
8750-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
103
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1352-8
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Apparent diffusion time of oxygen from blood to tissue in rat cerebral cortex: implication for tissue oxygen dynamics during brain functions.
pubmed:affiliation
Department of Radiology and Nuclear Medicine, Akita Research Institute for Brain and Blood Vessels, Akita, Japan. masamoto@nirs.go.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural