Document Detail


Adenosine stimulates breathing in fetal sheep with brain stem section.
MedLine Citation:
PMID:  1537749     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Breathing responses to adenosine were determined in 12 chronically catheterized fetal sheep (greater than 0.8 term) in which hypoxic inhibition of breathing had been eliminated by brain stem section. The caudal extent of transection varied from the rostral midbrain to the pontomedullary junction. Isocapnic hypoxia [delta arterial PO2 (PaO2) of -12 Torr] doubled the incidence and depth of breathing activity and increased the incidence of eye movements. Intra-arterial infusion of adenosine (0.30 +/- 0.03 mg.min-1.kg fetal wt-1) increased the incidence and amplitude of breathing without affecting blood gases. Adenosine did not significantly alter the incidence of eye activity. Intra-arterial injection of oligomycin (120 +/- 26 micrograms/kg fetal wt), an inhibitor of mitochondrial oxidative phosphorylation, also stimulated breathing activity. In four fetuses with brain stem section, peripheral arterial chemodenervation blunted the stimulatory effects of hypoxia on breathing activity and abolished altogether the excitatory effects of adenosine. It is concluded that 1) hypoxia and adenosine likely inhibit breathing in normal fetuses by affecting similar areas of the brain stem and 2) in fetuses with brain section, hypoxic hyperpnea depends on peripheral and central mechanisms, whereas adenosine stimulates breathing via the peripheral arterial chemoreceptors.
Authors:
B J Koos; A Chao; W Doany
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  72     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1992 Jan 
Date Detail:
Created Date:  1992-03-30     Completed Date:  1992-03-30     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:  94-9     Citation Subset:  IM    
Affiliation:
Department of Obstetrics and Gynecology, Nicholas S. Assali Perinatal Research Laboratory, University of California, Los Angeles School of Medicine 90025.
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MeSH Terms
Descriptor/Qualifier:
Adenosine / pharmacology*
Animals
Brain Stem / physiology*
Chemoreceptor Cells / physiopathology
Denervation
Female
Fetal Hypoxia / physiopathology
Fetus / drug effects*,  physiology
Oligomycins / pharmacology
Pregnancy
Respiration / drug effects*,  physiology
Sheep
Grant Support
ID/Acronym/Agency:
HD-18478/HD/NICHD NIH HHS
Chemical
Reg. No./Substance:
0/Oligomycins; 58-61-7/Adenosine

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


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