Document Detail


The role of adenosine in regulation of cerebral blood flow during hypoxia in the near-term fetal sheep.
MedLine Citation:
PMID:  12231655     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The aim of this study was to determine in the near-term ovine fetus the role of adenosine in the basal regulation of cerebral blood flow and in the increases in cerebral blood flow in response to acute hypoxic insult. We measured cerebral blood flow in chronically instrumented fetal sheep (127-135 days gestation, term approximately 145 days) using laser Doppler flowmetry probes implanted in the parietal cortices. Hypoxia was administered for 30 min by lowering the ewe's inspired oxygen to 10-12 % during an infusion of either saline or theophylline, a non-specific adenosine receptor antagonist. The theophylline infusion was begun 30 min prior to and ended 30 min after the completion of the hypoxic insult. The administration of theophylline had no significant effect on cerebral blood flow during the baseline period. During control hypoxic periods, cerebral blood flow increased by approximately 45 %. During theophylline experiments, however, there was no significant increase in cerebral blood flow during hypoxia. In the control experiments, cerebral blood flow returned to baseline levels during the recovery period, while in the theophylline experiments cerebral blood flow fell below baseline levels. We conclude that, in the near-term ovine fetus, adenosine plays a minimal role in the regulation of basal cerebral blood flow. However, these data are strong evidence for the involvement of adenosine in increased fetal cerebral blood flow during an acute hypoxic insult. Finally, adenosine may also play an important role in the maintenance of fetal cerebral blood flow immediately following hypoxic insult.
Authors:
Arlin B Blood; Christian J Hunter; Gordon G Power
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of physiology     Volume:  543     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2002 Sep 
Date Detail:
Created Date:  2002-09-16     Completed Date:  2003-02-25     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1015-23     Citation Subset:  IM    
Affiliation:
Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
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MeSH Terms
Descriptor/Qualifier:
Adenosine / blood,  physiology*
Animals
Blood Glucose
Blood Pressure
Carbon Dioxide / blood
Cerebrovascular Circulation / drug effects*,  physiology*
Female
Gestational Age
Heart Rate
Hemoglobins
Hydrogen-Ion Concentration
Hypoxia, Brain / physiopathology*
Injections, Intravenous
Lactic Acid / blood
Laser-Doppler Flowmetry
Oxygen / blood
Pregnancy
Purinergic P1 Receptor Antagonists
Theophylline / pharmacology
Vascular Resistance / drug effects,  physiology
Vasodilator Agents / pharmacology
Grant Support
ID/Acronym/Agency:
HL65494/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Hemoglobins; 0/Purinergic P1 Receptor Antagonists; 0/Vasodilator Agents; 124-38-9/Carbon Dioxide; 50-21-5/Lactic Acid; 58-55-9/Theophylline; 58-61-7/Adenosine; 7782-44-7/Oxygen
Comments/Corrections

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