Mechanisms Study Of Ketamine In Analgesic Effect

Objective To observe the analgesic effect of Ketamine in rats and the effect of the correlated transmittance and gene in the cerebral cortex of rats. Methods Fifty male SD rats weighing(250±20)g were randomly divided into five groups of 10 animals of each:Normal control group,Saline group, Ketamine groups(5mg/kg,10mg/kg and 20mg/kg).According to the Brennan's method to build an incision pain model in the rat's digiti pedis,cumulative pain score and cold stimulation score were utilized to assess pain behavior of the incision pain model.The cerebral cortex was removed at 30min after administration to measure NO production,NOS activity and concentration of the tissue protein respectively with the NOS kit,NOS kit and Coomassie kit;to measure NMDAR1 and c-fos genes expression with RT-PCR method.Results (1)Cumulative pain scores equation in 10,20mg/kg Ket groups were higher than normal saline group,however,cold stimulative scores were lower than normal saline group.When compared with normal saline group,there were significant difference.(2)When compared with normal saline group,10,20mg/kg Ket groups could decrease NO contents,attenuate NOS activity and inhibit NMDAR1 and c-fos genes expression in the cerebral cortex.When compared with normal saline group,there were statistical difference. Conclusion It could produce the antinociceptive effect by subcutaneous administration of different dosage Ketamine in a rat model of incisional pain; When the NOS activity was degraded by intercepting NMDAR1,stopping Ca²⁺ inflow by Ketamine,NO production was stopped,and the NMDAR1,c-fos genes expression was inhibited at the same time.