ABSTRACT
Objective To investigate formalin-induced nociceptive behavior and c-fos expression of interbrain following stellate ganglionic block (SGB) in rabbits. Methods Catheters were inserted closely to right stellate ganglia in rabbits by operation.One week later,twenty-four rabbits were randomly divided into three groups, each group containing 8 animals. groups A,B and C received 0.5ml of normal saline,3% formalin and 3% formalin stimulation by intraplantar injection , respectively. 10 minutes before stimulation,0.5 ml of 0.25% bupivacaine was administered via the catheter in group B, while in groups A and C 0.5 ml of normal saline was applied. Nociceptive behavior was observed for 1 hour using weighted pain score. 2 hours after stimulation, whole interbrain was removed to immunohistochemically detect the expression of c-fos. Results Formalin-induced nociceptive behavior in phase 2 was relieved following SGB, c-fos expression level of hypothalamus in group B was significantly lower than that in group C(P0.05). Conclusion SGB could relieve formalin-induced nociceptive behavior, and downregulate formalin-induced c-fos expression of hypothalamus, which may be related to the mechanisms of SGB for the treatment of inflammatory pain.