Document Detail

The cardiovascular effects of circulating catecholamines in fetal sheep.
MedLine Citation:
PMID:  745099     Owner:  NLM     Status:  MEDLINE    
1. Adrenaline and noradrenaline have been infused into the fetal sheep to produce plasma concentrations comparable to those seen during hypoxia and the cardiovascular changes compared with those seen in response to hypoxia. The effect of isoprenaline, methoxamine, and beta- and alpha-adrenergic antagonists were also investigated. 2. There were no significant changes in the blood gas values during any of the infusions except for a mean fall in pH of 0.04 during adrenaline infusion. 3. Adrenaline caused a fall in the fetal heart rate followed by a rise above the control value after 15-20 min. The fall in heart rate was abolished when the rise in blood pressure was blocked with phentolamine. The rise in heart rate was blocked by propranolol. The exact cause of the biphasic changes in heart rate during adrenaline infusion is not clear. 4. A fall in heart rate was not seen with noradrenaline; a small rise was. Propranolol changed this into a fall in heart rate while phentolamine increased the size of the heart rate rise. 5. Phentolamine alone increased the fetal heart rate by 25% and reduced blood pressure by 12%; propranolol alone reduced heart rate by 14% and had no effect on blood pressure. Isoprenaline increased fetal heart rate and reduced blood pressure. 6. The incidence of fetal breathing movements was highly variable. Despite this a significant increase was observed during adrenaline infusion. None of the other infusions had consistent effects. 7. The role of the circulating catecholamines in mediating or modifying the cardiovascular responses to hypoxia in the fetal sheep is discussed.
C T Jones; J W Ritchie
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of physiology     Volume:  285     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  1978 Dec 
Date Detail:
Created Date:  1979-05-24     Completed Date:  1979-05-24     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  381-93     Citation Subset:  IM    
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MeSH Terms
Blood Pressure / drug effects
Carbon Dioxide / blood
Epinephrine / blood*,  pharmacology
Fetal Heart / physiology*
Heart Rate / drug effects
Isoproterenol / pharmacology
Methoxamine / pharmacology
Norepinephrine / blood*,  pharmacology
Oxygen / blood
Phentolamine / pharmacology
Propranolol / pharmacology
Respiration / drug effects
Reg. No./Substance:
124-38-9/Carbon Dioxide; 390-28-3/Methoxamine; 50-60-2/Phentolamine; 51-41-2/Norepinephrine; 51-43-4/Epinephrine; 525-66-6/Propranolol; 7683-59-2/Isoproterenol; 7782-44-7/Oxygen

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

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