Influence of brain catecholamines on the development of fatigue in exercising rats in the heat
Open Access
- 2 January 2008
- journal article
- Published by Wiley in The Journal of Physiology
- Vol. 586 (1), 141-149
- https://doi.org/10.1113/jphysiol.2007.142190
Abstract
The purpose of the present study was to identify the effects of an acute injection of a dual dopamine (DA)/noradrenaline (NA) reuptake inhibitor (bupropion) on exercise performance, thermoregulation and neurotransmitters in the preoptic area and anterior hypothalamus (PO/AH) of the rat during exercise in the heat. Body core temperature (Tcore), brain temperature (Tbrain) and tail skin temperature (Ttail) were measured. A microdialysis probe was inserted in the PO/AH, and samples for measurement of extracellular DA, NA and serotonin (5‐HT) levels were collected. Rats received either bupropion (17 mg kg−1; hot‐BUP) or saline (1 ml kg−1; hot) 20 min before the start of exercise and ran at a speed of 26 m min−1 until exhaustion in a warm environment (30°C). Rats also ran until exhaustion in a cool environment (18°C; cool). Running time to exhaustion was significantly influenced by the ambient temperature, and it was increased by bupropion in the heat (cool, 143.6 ± 21 min; hot, 65.8 ± 13 min; hot‐BUP, 86.3 ± 7.2 min). Tcore and Tbrain at exhaustion were significantly higher in the bupropion group compared to the cool and hot groups, respectively. Ttail measured at exhaustion was not significantly different between the two hot conditions. Extracellular concentrations of DA and NA in the PO/AH increased during exercise, and was significantly higher in the bupropion than in cool and hot groups (P < 0.05). No differences were observed between groups for 5‐HT levels. These results suggest that DA and NA in the PO/AH might be responsible for the increase in exercise performance and Tcore and Tbrain in the bupropion group in hyperthermia. Moreover, these results support previous findings in humans that acute bupropion ingestion increases Tcore during exercise in the heat, indicating the possibility of an important role for DA and NA in thermoregulation.Keywords
This publication has 50 references indexed in Scilit:
- How the body controls brain temperature: the temperature shielding effect of cerebral blood flowJournal of Applied Physiology, 2006
- Alterations in Blood–Brain Barrier Function by Morphine and MethamphetamineAnnals of the New York Academy of Sciences, 2006
- Cooling Athletes before Competition in the HeatSports Medicine, 2006
- Hormonal responses during prolonged exercise are influenced by a selective DA/NA reuptake inhibitorBritish Journal of Sports Medicine, 2004
- Hyperthermia induced pathophysiology of the central nervous systemInternational Journal of Hyperthermia, 2003
- Exercise Performance is not Influenced by a 5-HT Reuptake InhibitorInternational Journal of Sports Medicine, 2001
- Limits to Exercise Performance in the HeatInternational Journal of Sports Medicine, 1998
- Endurance Performance in Humans: The Effect of a Dopamine Precursor or a Specific Serotonin (5-HT2A/2C) AntagonistInternational Journal of Sports Medicine, 1997
- Exercise and Brain NeurotransmissionSports Medicine, 1995
- Temperature Receptors in the Central Nervous SystemAnnual Review of Physiology, 1986