Antipyretic action of peripheral stimulation with electroacupuncture in rats

The present study was designed to investigate the antipyretic action of peripheral stimulation with electroacupuncture (EA) in SD rats. EA stimulation was applied for 30 min to the peripheral muscle where the equivalent Quchi (LI11) acupoint is located. We first examined the effects of EA stimulation on fever induced by either lipopolysaccharide (LPS), interleukin-1 beta (IL-1 beta) or prostaglandin E2 (PGE2). Intraperitoneal injection of LPS at a dose of 100 micrograms/kg caused a high rectal temperature, which was suppressed by EA stimulation. EA stimulation also inhibited the development of fever induced by IL-1 beta injection either intravenously or into the preoptic area (POA). The rats that received administration of PGE2 into POA developed rapid and high fevers, which were attenuated by EA stimulation. In the second part of the experiment, we investigated the levels of cytokines and PGE2 during the development of fever. The concentrations of IL-6 and PGE2 but not IL-1 beta, in brain and serum were increased by intraperitoneal injection of 100 micrograms/kg LPS. EA stimulation reduced PGE2 levels in both brain and serum in LPS-injected rats, but failed to change the levels of IL-6. Intravenous injection of IL-1 beta produced high brain and serum PGE2 levels, which were also significantly suppressed by EA stimulation. The results suggest that EA stimulation possesses an antipyretic effect through the inhibition of the action of PGE2 in rats.