Acute dopamine/norepinephrine reuptake inhibition increases brain and core temperature in rats

Abstract

The purpose of the present study was to examine the effects of an acute dose of the dual dopamine (DA) and norepinephrine (NE) reuptake inhibitor bupropion (Bup) on brain (Tbrain), body core (Tcore), and tail skin (Ttail) temperature in freely moving rats and to simultaneously monitor the extracellular neurotransmitter concentrations in the preoptic area and anterior hypothalamus (PO/AH). A microdialysis probe was inserted in the PO/AH, and samples for NE, DA, and serotonin (5-HT) were collected every 20 min before and after the injection of 17 mg/kg of Bup, for a total sampling time of 180 min. Tcore was monitored using a biotelemetry system. Tbrain and Ttail, an index of heat loss response, were also measured. Both NE and DA levels in the PO/AH significantly increased after Bup injection compared with the baseline levels, reaching ∼450 and 230%, respectively, 40 min after injection. There was no effect on 5-HT release. The neurotransmitter changes were accompanied by a significant decrease in Ttail and an increase in both Tbrain and Tcore compared with the baseline levels. The present results demonstrate that inhibition of NE and DA reuptake suppresses heat loss mechanisms and elevates Tbrain and Tcore in freely moving rats.