Document Detail


Catecholamines contribute to exertional dyspnoea and to the ventilatory response to exercise in normal humans.
MedLine Citation:
PMID:  9402459     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Exogenous catecholamine administration in humans stimulates ventilation. The present study was designed to investigate whether increased endogenous catecholamine release influences objective measures of ventilation and subjective measures of breathlessness in normal subjects. METHODS: Yohimbine, a pre-synaptic alpha 2 adrenoceptor antagonist, or placebo was administered to 10 normal male subjects in a double-blind cross-over fashion. Ventilation and metabolic gas exchange were measured during steady state exercise at 60% of previously determined maximal oxygen consumption. Venous lactate and noradrenaline were measured during exercise. Subjects' sensation of breathlessness and fatigue were recorded using visual analogue scales. RESULTS: Plasma noradrenaline was higher following yohimbine administration (at 6 min exercise; 4.58 +/- 0.56 nmol.l-1 vs 8.74 +/- 1.53; P < 0.05). Oxygen consumption was unchanged, but ventilation was greater throughout exercise following yohimbine. The sensation of exertion was greater following yohimbine, and at any given level of ventilation, the sensation of exertion was greater. CONCLUSIONS: Yohimbine administration causes increased noradrenaline release. This is associated with an increased ventilatory response and an increase in the sensation of exertion during steady state exercise. An increase in circulating noradrenaline might be a mechanism for both increased ventilation and pathological conditions of breathlessness such as chronic heart failure.
Authors:
A L Clark; S Galloway; N MacFarlane; E Henderson; T Aitchison; J J McMurray
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article    
Journal Detail:
Title:  European heart journal     Volume:  18     ISSN:  0195-668X     ISO Abbreviation:  Eur. Heart J.     Publication Date:  1997 Nov 
Date Detail:
Created Date:  1998-01-28     Completed Date:  1998-01-28     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8006263     Medline TA:  Eur Heart J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1829-33     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Glasgow, UK.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic alpha-Antagonists / pharmacology
Adult
Catecholamines / physiology*
Cross-Over Studies
Double-Blind Method
Dyspnea / physiopathology*
Humans
Lactates / blood
Male
Norepinephrine / blood
Physical Exertion*
Yohimbine / pharmacology
Chemical
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Catecholamines; 0/Lactates; 146-48-5/Yohimbine; 51-41-2/Norepinephrine

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