RESUMO
Objective To explore the mechanism of N-methyl-D-aspartic acid ( NMDA) receptor/MAPK/cAMPresponse element binding protein ( CREB) pathway involved in pain-related aversion mediated by anterior cingulate cortex. Methods A total of 42 healtlry SD rats were randomly divided into control group (Ctrl) , normal saline(NS) injection group (NS) , complete freund adjuvant (CFA) model group ( CFA ) , injected CFA into the soles of the foot and injected NS into rostral part of anterior cingulate cortex (rACC)group (CFA+NS) , injected NS into the soles of the foot and injected NS into rACC group (NS+NS) , injected CFA into the soles of the foot and injected NMDA receptor antagonist ( APV ) into rACC group (CFA+APV) , injected NS into the soles of the foot and injected APV into rACC group ( NS + APV ) with 6 rats in each group. Rats avoidance score was analysised and rat thermal foot contraction latency ( PWL) ws alserved, the expression of NMDA receptor in rACC region was detected by immunohistochemical staining, the expression of NMDA receptor, phosphorylated ERK( p-ERK) and phosphorylated CREB ( p - CREB ) in rACC region was detected by immunofluorescent staining, the number of Nissl bodies in rACC region was observed by Nissl staining, and the expression of NMDA receptor, MAPK, CREB, ERK, p-ERK, p-CREB, synaptosomal-associated protein 25 interaction protein 30 (SIP30) protein in rACCregion was detected by Western blotting, and Real-time PCR was used to detect the mRNA expression of NMDA receptor, MAPK, CREB and ERK in the rACC region. Results Compared with the Ctrl group, the avoidance score and PWL decreased significantly and the expression of NMDA receptor, MAPK and CREB increased significantly in the CFA group (P<0. 05). Compared with the CFA+NS group, the number of Nissl bodies in CFA+APV and NS+APV groups increased significantly, while the expression of NMDA receptor, MAPK, CREB, p-ERK and p-CREB decreased significantly in NS+NS and NS+APV groups (P<0. 05). Conclusion NMDA receptor-MAPK-CREB signal pathway in rACC is involved in painrelated aversion, and inhibition of NMDA can reduce pain-related negative aversion.