Abstract: ObjectiveTo investigate effects of electroacupuncture(EA) of Zusanli(ST36) on changes of substance P(SP) mRNA expression in rat brain stem.Methods78 SD rats were evenly randomized into Zuanli-EA group, non-acupoint group, bondage groups(at the end of 2h,4h,6h,8h after 30 minute EA stimulation in each group) and control group. RT-PCR and image processing were used to study the change of SP mRNA level in brain stem.ResultsIn control groups,there was SP expression. An increase of SP mRNA expression was seen in Zusanli group and non-acupoint group comparing with control group at the end of 2h after 30min EA stimulation(P<0.05).There was difference between above two groups at the end of 6h and 8h(P<0.05).ConclusionEA stimulation elicited an accelerated expression of SP gene. Zusanli-EA stimulation can increased this expression, which may constitute one of the mechanisms for gastrointestinal motility and eletroacupuncture analgesia.

Key words: electroacupuncture, Zusanli(ST36), substance P, gene expression, brain stem, rats