Short- and long-term administration of buprenorphine improved gene expression of PX and GABAA receptors in the hippocampus of methamphetamine rats.

PX receptors modulate synaptic transmission and communication among neurons in the CNS. An increased level of neuronal PX is associated with altered memory in the hippocampal region. Additionally, some evidence suggests that PX receptors downregulate the GABA receptors. In the microglia of drug users, methamphetamine (METH) modifies the expression of certain genes. Therefore, the alterations of PX and GABA gene expression on memory following treatment with/without buprenorphine (BUP) in METH rats were evaluated. Seventy-seven rats were allocated into eleven groups at random (n = 7). Control, METH (10 mg/kg), BUP (6 and 10 mg/kg) for 5 days, BUP (6 and 10 mg/kg) for 14 days, METH (10 mg/kg) + BUP (6 and 10 mg/kg) for 5 days, METH + BUP (6 and 10 mg/kg) for 14 days and withdrawal group. They received their treatments intraperitoneally. After memory assessment, the animals were decapitated, and the gene expression of PX and GABA receptors in the hippocampus was assayed using RT-PCR. The memory and PX and GABA receptor gene expression in METH rats were reduced compared to the control group. The administration of all the different BUP doses increased gene expression in (BUP 6 or 10 mg/kg. 5 days and BUP.10 mg/kg.14 days) + METH groups compared to METH rats. These results demonstrated that METH toxicity severely decreased the level of PX gene expression. Meanwhile, treatment of BUP led to increasing levels of the mentioned gene. Therefore, the potential role of PX and GABA receptor genes in modulating METH addiction is addressed.