〔Abstract〕 Objective To investigate the effect of adeno-associated virus(AAV) delivery of short hairpin RNA(shRNA) against the Ptger3 gene in the lateral parabrachial nucleus(LPB) on the fever induced by microinjection of prostaglandin E2(PGE2) into the LPB and the intraperitoneal injection of lipopolysaccharide(LPS). Methods AAV2-shRNA-Ptger3(EP3)-EGFP(shRNA-EP3) and AAV2-CMV-EGFP(shRNA-control) viruses were constructed and transfected the rat LPB by stereotaxic injection. Four weeks later, the transfection efficiency of AAV viruses was observed by fluorescence microscopy, and the knockdown efficiency was determined by real-time PCR of EP3 receptor mRNA on the LPB. The effects of microinjection of saline or PGE2in the LPB or intraperitoneal injection of LPS on body temperature(Tcore) and energy expenditure(EE) of shRNA-control group and shRNA-EP3 group were monitored using an animal monitoring system with temperature telemetry. Results AAV virus transfection of shRNA-EP3 group and shRNA-control group was mainly found in the LPB. The EP3 receptor mRNA level in LPB of shRNA-EP3 group was reduced compared with that of shRNA-control group(P<0.05). There was no significant difference in basal body temperature between shRNA-control group and shRNA-EP3 group. Tcoreand EE were briefly and slightly increased after microinjection of saline in the LPB, but there was no significant difference between the two groups. Compared with the shRNA-control group, the febrile response induced by LPB PGE2was attenuated in the shRNA-EP3 group(P<0.05). Furthermore, the knockdown of EP3 receptor of LPB also attenuated the LPS-induced fever, and the Tcore5.5 h post-LPS in the shRNA-EP3 rats increased compared with the baseline(P<0.05), which was lower than that in the shRNA-control rats(P<0.01). Conclusion EP3 receptor knockdown in LPB attenuates the febrile response induced by microinjection of PGE2in the LPB and intraperitoneal injection of LPS, suggesting that EP3 receptors of LPB mediate the pyrogenic action of LPB PGE2and partly participate in LPS-induced fever.