Document Detail


Dopamine does not limit fetal cerebrovascular responses to hypoxia.
MedLine Citation:
PMID:  17209159     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Dopamine is used clinically to stabilize mean arterial blood pressure (MAP) in sick infants. One goal of this therapeutic intervention is to maintain adequate cerebral blood flow (CBF) and perfusion pressure. High-dose intravenous dopamine has been previously demonstrated to increase cerebrovascular resistance (CVR) in near-term fetal sheep. We hypothesized that this vascular response might limit cerebral vasodilatation during acute isocapnic hypoxia. We studied nine near-term chronically catheterized unanesthetized fetal sheep. Using radiolabeled microspheres to measure fetal CBF, we calculated CVR at baseline, during fetal hypoxia, and then with the addition of an intravenous dopamine infusion at 2.5, 7.5, and 25 microg.kg(-1).min(-1) while hypoxia continued. During acute isocapnic fetal hypoxia, CBF increased 73.0 +/- 14.1% and CVR decreased 38.9 +/- 4.9% from baseline. Dopamine infusion at 2.5 and 7.5 microg.kg(-1).min(-1), begun during hypoxia, did not alter CVR or MAP, but MAP increased when dopamine infusion was increased to 25 microg.kg(-1).min(-1). Dopamine did not alter CBF or affect the CBF response to hypoxia at any dose. However, CVR increased at a dopamine infusion rate of 25 microg.kg(-1).min(-1). This increase in CVR at the highest dopamine infusion rate is likely an autoregulatory response to the increase in MAP, similar to our previous findings. Therefore, in chronically catheterized unanesthetized near-term fetal sheep, dopamine does not alter the expected cerebrovascular responses to hypoxia.
Authors:
Dennis E Mayock; Rachel Bennett; Roderick D Robinson; Christine A Gleason
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  102     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2007 Jan 
Date Detail:
Created Date:  2007-01-08     Completed Date:  2007-03-13     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  130-4     Citation Subset:  IM    
Affiliation:
Division of Neonatology, Department of Pediatrics, University of Washington, Seattle, Washington 98195-6320, USA. mayock@u.washington.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Anoxia / physiopathology*
Blood Pressure / drug effects,  physiology
Cerebrovascular Circulation / drug effects*,  physiology
Dopamine / pharmacology*
Dopamine Agents / pharmacology*
Dose-Response Relationship, Drug
Female
Fetus / blood supply*,  physiopathology
Heart Rate / drug effects,  physiology
Homeostasis / drug effects,  physiology
Pregnancy
Regional Blood Flow / drug effects,  physiology
Sheep
Vasodilation / drug effects,  physiology
Grant Support
ID/Acronym/Agency:
R01-NS-34057/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/Dopamine Agents

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


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