Abstract
We recently reported that an acute injection of a dual dopamine (DA)/noradrenaline (NA) reuptake inhibitor bupropion improved exercise performance in the heat while providing high brain and abdominal temperature and an increased levels of DA and NA in the preoptic area and anterior hypothalamus (PO/AH) of the rat (Hasegawa et al., 2007). In the present study, we attempted to identify the effects of acute dose of dopamine D2 receptor agonist quinpirole on brain (Tbrain), core (Tcore) and tail skin temperature (Ttail) in freely moving rats, and to simultaneously monitor the extracellular DA concentrations in the PO/AH using brain microdialysis. A telemetry device was implanted into the peritoneal cavity and an intracerebral guide was implanted in the left PO/AH for the microdialysis probe. On the day of the experiments, rats received either an intraperitoneal injection of quinpirole (0.1 or 1 mg/kg) or saline (1ml/kg). Both Tbrain and Tcore significantly decreased after quinpirole (1mg/kg) injection compared with the baseline levels. Ttail, an index of heat loss response, significantly increased after injection of quinpirole (1mg/kg). These thermal changes were accompanied by a significant increase in DA level in the PO/AH. [J Physiol Sci. 2008;58 Suppl:S100]
