Catecholamines contribute to exertional dyspnoea and to the ventilatory response to exercise in normal humans

Clark, A.L., Galloway, S., MacFarlane, N., Henderson, E., Aitchison, T. and McMurray, J.J.V. (1997) Catecholamines contribute to exertional dyspnoea and to the ventilatory response to exercise in normal humans. European Heart Journal, 18(11), pp. 1829-33. (doi:10.1093/oxfordjournals.eurheartj.a015179) (PMID:9402459)

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Abstract

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 a2 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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McMurray, Professor John and MacFarlane, Dr Niall
Authors: Clark, A.L., Galloway, S., MacFarlane, N., Henderson, E., Aitchison, T., and McMurray, J.J.V.
College/School:College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:European Heart Journal
Journal Abbr.:Eur. heart j.
Publisher:Oxford University Press
ISSN:0195-668X
ISSN (Online):1522-9645

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