ObjectiveTo investigate the effects of prostaglandin E₂ （PGE₂） microinjection into the median preoptic nucleus （MnPO） on core body temperature in female mice， and to clarify its underlying mechanism. MethodsMicroinjection cannula were implanted into the MnPO of female mice using stereotaxic surgery.Subsequently， a multi-channel temperature acquisition system was used to simultaneously monitor rectal and brown adipose tissue （BAT） temperatures before and after intra-MnPO injections of different reagents.To investigate the thermoregulatory effects of the microinjection of PGE₂ into the MnPO， 12 female C57BL/6 mice were randomly divided into a saline group （n=6） and a PGE₂ group （n=6）， which were injected with 0.1 μL saline and PGE₂ （2.8 mmol/L）， respectively.To determine whether E-series prostaglandin receptor （EP）1， EP3， and EP4 receptors mediate the thermoregulatory effects of PGE₂， 15 female C57BL/6 mice were randomly divided into 3 groups （n=5 per group）.Mice in each group first received an injection of 0.1 μL PGE2 （2.8 mmol/L） into the MnPO. After their body temperature returned to baseline levels， they were subsequently injected with a mixture of either EP1， EP3 or EP4 antagonist （ant） （20 mmol/L） + PGE2 （2.8 mmol/L）. ResultsCompared with baseline level， the rectal temperature （P<0.01） and BAT temperature （P<0.001） of female mice both increased significantly after microinjection of PGE₂ into the MnPO.Compared with the saline group， the increases in rectal temperature （P<0.001） and BAT temperature （P<0.000 1） were significantly greater in the PGE₂ group of mice.Furthermore， following the injection of PGE₂ into MnPO， the increase in BAT temperature was found to be significantly greater than that in rectal temperature in mice （P<0.001）.Compared to the administration of PGE₂ alone， co-injection of an EP3 ant + PGE₂ into the MnPO of mice resulted in a significantly smaller increase in both rectal temperature （P<0.001） and BAT temperature （P<0.001）.In contrast， the increases in rectal and BAT temperatures following MnPO injection of either EP1 ant + PGE₂ or EP4 ant + PGE₂ were not statistically significant （P>0.05）. ConclusionInjection of PGE₂ into the MnPO elevates BAT and core body temperature in female mice via the EP3 receptor.