Studies on the Stimulating Effects of Adrenaline and Noradrenaline on Respiration in Man

Adrenaline infused intravenously at a rate of 0.15 μ g/kg/min increased the ventilation and CO 2 ‐elimination by a maximum of 45% in experiment on man. Since adrenaline increased the CO 2 tension and decreased the pH in the plasma of arterial blood, the respiratory increase after adrenaline was assumed to depend, at least in part, on an increased CO 2 ‐production of metabolic origin. About half of the increase in CO 2 ‐production was estimated to be due to raised oxygen consumption and the remaining half to have come from the plasma and tissue bicarbonate. The reduction of tissue bicarbonate was to a large part caused by an increased lactic acid and FFA concentration. The stimulating effect on respiratin of noradrenaline was initially associated with a decrease in plasma pCO 2 and an increased plasma pH. The initial increase in CO 2 ‐elimination which took place was assumed ro result from washing out of CO 2 The possibility that noradrenaline had stimulated O 2 ‐sensitive chemoreceptors is discussed. In a later stage noradrenaline probably stimulated the respiration through an increased oxygen consumption and CO 2 ‐production.