Objective:To observe the influence of damaging celiac ganglion(CG)by high intensity focused ultrasound(HIFU)on expression of substance P(SP) in spinal cord following gastric distension in rabbits

and study whether SP participate in transferring pain information as neurotransmitter. Mothods:20 rabbits were randomly divided into four groups in a 2 ×2 factorial design:not distended not damaged(nDnB)

distended not damaged(DnB)

not distendedly damaged(nDB)

distendedly damaged(DB)

with 5 in each group. At first

group nDB and DB were damaged by HIFU

group nDnB and DnB not damaged. 7 days later

they all were installed with the device of gastric distension. In group nDB and nDnB

tissue were directly fixed through infusing 4% parafomaldehyde under deep anaesthesia

then spinal cord of thoracic 6￣8(T6￣T8) was extracted. In group DB and DnB stomach was distended for 1 h

and the spinal cord were extracted in the way similar to that in the above two groups. Immunohistochemistry technique of strept avidin biotin complex(SABC)was used to display the content of SP in spinal cord. Results:In lamina and Ⅱ of dorsal horn

damaged CG could induce the OD in afferent projections and medial zone to increas significantl(yP<0.01). Gastric distension could induce the OD in lateral zone to increase significantl(yP<0.01). After CG was damaged

the increase of OD in lateral zone significantly descended(P<0.01).Conclusion:Gastric distension could induce the expressionof SP in thoracic slices to increase significantly. After CG is damaged

that increase induced by gastric distension in lateral zone lamina Ⅰ and Ⅱof dorsal horn significantly descends.