Nociceptive threshold response and alterations of special genes expression duringmethamphetamine administration and treatment with buprenorphine

Introduction: methamphetamine is a nerve stimulant. buprenorphine has been widely used in themanagement of various types of pain and reducing addiction side effects. this study aimed toinvestigate the role of methamphetamine, buprenorphine, or their interaction on analgesic threshold andthe expression of protein kinase b (akt) and glycogen synthase kinase 3 (gsk3b) genes in the lumbarspinal cord of male rats.materials and methods: in this experimental study, 56 male wistar rats (weight 200 ± 50 g) wererandomly divided into eight groups: the control group, sham group, methamphetamine group, twobuprenorphine groups, two methamphetamines + buprenorphine groups, and deprivation group. thedrugs of methamphetamine and buprenorphine were injected intraperitoneal (i.p) for five days. tomeasure the analgesic threshold, the tail-flick test was used. additionally, the real-time pcr techniquewas applied to evaluate the expression levels of akt and gsk3b genes in the lumbar spinal cord ofmale rats. a one-way anova test was used to analyze the data.results: intraperitoneal injection of methamphetamine (10 mg/kg) induced analgesia (p < 0.05) andincreased the expression of the gene of akt (p < 0.05) in the lumbar spinal cord of male rats. inaddition, the injection of buprenorphine (6 and 10 mg/kg) potentiated the effect of methamphetamineon analgesia (p < 0.01) and increased the expression of the gsk3b gene (p < 0.05), whereas the higherdose of buprenorphine reduced the impact of methamphetamine on the expression of akt gene (p <0.05). furthermore, the deprivation of methamphetamine, did not alter tail flick latency and theexpression level of akt and gsk3b genes.conclusion: our results indicated a possible reinforcing role of the buprenorphine on the increasingimpact of acute methamphetamine injection on the expression of the gsk3b gene and analgesia.