BACKGROUND: Exogenous @entity2922 administration in @entity1 stimulates ventilation. The present study was designed to investigate whether increased endogenous @entity2922 release influences objective measures of ventilation and subjective measures of breathlessness in normal subjects. METHODS: @entity3160 , 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 @entity26 consumption. Venous @entity880 and @entity1063 were measured during exercise. Subjects' sensation of breathlessness and fatigue were recorded using visual analogue scales. RESULTS: Plasma @entity1063 was higher following @entity3160 administration (at 6 min exercise; 4.58 +/- 0.56 nmol.l-1 vs 8.74 +/- 1.53; P < 0.05). @entity26 consumption was unchanged, but ventilation was greater throughout exercise following @entity3160 . The sensation of exertion was greater following @entity3160 , and at any given level of ventilation, the sensation of exertion was greater. CONCLUSIONS: @entity3160 administration causes increased @entity1063 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 @entity1063 might be a mechanism for both increased ventilation and pathological conditions of breathlessness such as @entity712 .

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

@entity1 :: ('9606', 'Species') :: ['humans'] @entity3160 :: ('MESH:D015016', 'Chemical') :: ['yohimbine', 'Yohimbine'] @entity712 :: ('MESH:D006333', 'Disease') :: ['chronic heart failure'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen', 'Oxygen'] @entity880 :: ('MESH:D019344', 'Chemical') :: ['lactate'] @entity2922 :: ('CHEBI:33567', 'Chemical') :: ['catecholamine'] @entity1063 :: ('MESH:D009638', 'Chemical') :: ['noradrenaline']
@entity1 :: (9606,Species) :: ['humans']
