Genetic knockout of the G protein-coupled estrogen receptor 1 facilitates the acquisition of morphine-induced conditioned place preference and aversion in mice.

Drug addiction is considered the pathological usurpation of normal learning and memory. G protein-coupled estrogen receptor 1 (GPER1) plays an important role in normal learning and memory, but the effect of GPER1 on addiction-related pathological memory has not been reported. Our study used GPER1 knockout (GPER1 KO) and wild-type (WT) mice to compare the sensitivity differences of morphine- and sucrose-induced conditioned place preference (CPP) and naloxone-induced conditioned place aversion (CPA), and differences in dopamine (DA) content in the nucleus accumbens (NAc) were determined by high performance liquid chromatography (HPLC). The results showed that GPER1 KO mice showed higher sensitivity to morphine-induced CPP and naloxone-induced CPA, and corresponding to the behavioral effect, the DA content in the NAc of GPER1 KO mice was significantly higher than that of WT mice. Interestingly, the sensitivity of GPER1 KO mice to sucrose-induced CPP did not differ from that of the WT mice, and there was no significant difference in the DA content in the NAc between the two genotypes of mice. GPER1 knockout promoted the formation of morphine addiction-related positive and aversive memory, and its molecular biological mechanism may be associated with increased DA content in the NAc. Therefore, GPER1 plays an important role in the formation of addiction-related pathological memory and may become a potential molecular target for drug addiction therapy.

Narcotic Addiction in Failed Back Surgery Syndrome.

Back pain is a common health problem that reduces the quality of life for human beings worldwide. Several treatment modalities have been reported as effective for pain relief. Generally, patients often undergo surgical interventions as pain becomes intractable, after conservative treatment. With advances in surgical techniques, those choosing spinal surgery as an option have increased over time, and instrumentation is more popular than it was years ago. However, some patients still have back pain after spinal operations. The number of patients classified as having failed back surgery syndrome (FBSS) has increased over time as has the requirement for patients receiving long-term analgesics. Because pain relief is regarded as a human right, narcotics were prescribed more frequently than before. Narcotic addiction in patients with FBSS has become an important issue. Here, we review the prevalence of FBSS, the mechanism of narcotic addiction, and their correlations. Additionally, several potentially effective strategies for the prevention and treatment of narcotic addiction in FBSS patients are evaluated and discussed.