european college of sport science

THE POSSIBLE ROLE OF SEROTONINE, DOPAMINE AND NORADRENALINE IN CENTRAL FATIGUE
ROELANDS, B., MEEUSEN, R.
VRIJE UNIVERSITEIT BRUSSEL
OP-PH04 Physiology 4
Introduction: The central fatigue hypothesis is based on the assumption that during prolonged exercise the synthesis and metabolism of
central monoamines, in particular serotonin (5-HT), dopamine (DA) and noradrenaline (NA), are influenced (Meeusen,2006). It is not
known however which neurotransmitter system is responsible for accelerating or delaying the onset of fatigue during prolonged exercise.
The influence of ambient temperature on fatigue is well studied, but there are little available data on the combined effects of pharmacological
manipulations and environmental heat stress on performance. Therefore, the effects of acute administration of individual 5-HT, DA
and NA reuptake inhibitors (5-HTRI, DARI, NARI) on performance and thermoregulation were examined in normal and high ambient
temperature.
Methods: In three separate studies, between 8 and 11 healthy trained male cyclists completed four experimental trials (two in 18°C, two in
30°C) in a double blind-randomized crossover design. Subjects ingested either a placebo or drug (Citalopram – 5-HTRI, Reboxetine -
NARI, Ritalin - DARI) on the morning of the trial. Subjects cycled for 60 min at 55%Wmax, immediately followed by a time trial to measure
performance. Tcore, skin temperature, heart rate, blood pressure, sweat loss, RPE, thermal stress, blood lactate and hormonal data were
recorded. The significance level was set at p