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This Article Full Text Full Text (PDF) All Versions of this Article: 586/1/141    most recent jphysiol.2007.142190v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hasegawa, H. Articles by Meeusen, R. Search for Related Content PubMed PubMed Citation Articles by Hasegawa, H. Articles by Meeusen, R. Related Collections Neuroscience

¹ Laboratory of Exercise Physiology, Graduate School of Faculty of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima, Japan
² Department of Human Physiology and Sports Medicine, Vrije Universiteit Brussel, Brussels, Belgium
³ Department of Pharmaceutical Chemistry and Drug Analysis, Research Group Experimental Pharmacology, Vrije Universiteit Brussel, Brussels, Belgium
⁴ Department of Human Movement and Sport Sciences, Istituto Universitario di Scienze Motorie, Rome, Italy
⁵ Junior College, University of Tokyo Social Welfare, Gunma, Japan

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 (T_core), brain temperature (T_brain) and tail skin temperature (T_tail) 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). T_core and T_brain at exhaustion were significantly higher in the bupropion group compared to the cool and hot groups, respectively. T_tail 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 T_core and T_brain in the bupropion group in hyperthermia. Moreover, these results support previous findings in humans that acute bupropion ingestion increases T_core during exercise in the heat, indicating the possibility of an important role for DA and NA in thermoregulation.

(Received 1 August 2007; accepted after revision 12 October 2007; first published online 18 October 2007)
Corresponding author R. Meeusen: Department of Human Physiology and Sports Medicine, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium. Email: rmeeusen{at}vub.ac.be