Inhaled salbutamol decreases blood ammonia levels during exercise in normal subjects

Abstract

The present study examines the effect of salbutamol, a beta2-adrenoreceptor agonist, on blood ammonia levels during an incremental cycle exercise test in healthy non-asthmatic subjects. Blood ammonia levels were lower after inhalation of 400 mcg of salbutamol than after placebo during submaximal exercise: 33+/-2 micromol x l(-1) v.s. 48+/-9 micromol x l(-1) at 220 W and 39+/-2 micromol x l(-1) v.s. 50+/-4 micromol x l(-1) at 260 W. At peak exercise there were no significant differences. The results suggest that beta2-adrenoreceptors are involved in the regulation of blood ammonia during exercise.

Inhaled Salbutamol and Endurance Cycling Performance in Non-Asthmatic Athletes

“…Also in our study, inhalation of salbutamol did not appear to further stimulate lipolysis above the level already taking place due to the exercise itself, because plasma FFA concentrations were similar after placebo and salbutamol. In agreement with these findings, Matthys et al [21] reported unchanged plasma FFAs during exercise after inhalation of 400 g salbutamol, although plasma glycerol concentrations tended to be increased in their study. Increased plasma lactate concentrations during exercise after salbutamol administration have been reported by several investigators [4,21,31], The increase is most probably due to beta 2 -adrenergic stimulation of glycolysis.…”

“…In agreement with these findings, Matthys et al [21] reported unchanged plasma FFAs during exercise after inhalation of 400 g salbutamol, although plasma glycerol concentrations tended to be increased in their study. Increased plasma lactate concentrations during exercise after salbutamol administration have been reported by several investigators [4,21,31], The increase is most probably due to beta 2 -adrenergic stimulation of glycolysis. However, the increase is not always found ( [5]; this study).…”

Fatigued muscles in COPD but no finishing line in sight

“…However, this is unlikely as it would imply that muscle fibre type distribution resembles that of the healthy controls who did show a rise in ammonia. An alternative, although very speculative, explanation could be a bias introduced through use of b 2 -adrenoreceptor agonists prior to the exercise test, since it has been shown that acute administration of these drugs decreases blood ammonia levels during exercise in healthy subjects [15]. A more plausible explanation, also provided by CALVERT et al [13], is that ATP supply met ATP demand during exercise in this subgroup.…”

Effect of Salbutamol on Neuromuscular Function in Endurance Athletes

“…Doses of inhaled A 2 -agonists of salbutamol, however, are more than 20 times smaller (100 Hg per puff) than oral (2 mg per pill up to 12-20 mgId j1 ) doses and are thought to act locally within the airways. Most studies, having tested the effect of inhalation of ''therapeutic'' (200 Hg) or even ''supratherapeutic'' (up to 800-1000 Hg) doses of A 2 -agonists on exercise performance, revealed no ergogenic effect (21,26,40). Our group showed in recreational sportsmen that acute inhalation of therapeutic (200 Hg) or supratherapeutic (800 Hg) doses of salbutamol did not significantly modify voluntary activation (VA), quadriceps contractility, and fatigue after whole-body or localized exercise (13).…”

“…First, salbutamol uptake was shown to induce some systemic effects, e.g., changes in resting heart rate (16), blood glucose concentration (36,37), ammonia (26), free fatty acids, glycerol, actate, and potassium (40). Thus, part of the inhaled A 2agonists dose may potentially reach the peripheral muscles.…”