左旋四氢帕马丁干预大鼠海洛因自身给药和复吸行为的机制研究

Repeated heroin use could result in drug addiction， meanwhile the treatment failure caused by relapse remains to be a major obstacle to the treatment of drug dependence. In this program, we aimed to investigate the effects of levo-tetrahydropalmatine (1-THP) on the development of heroin reinforcement and reinstatement in rat, as well as uncover the underlying mechanisms. This proposal was motivated by a recent clinical trial which suggested that 1-THP could help to reduce drug cravings and withdrawal symptons, as well as lower relapse rates during heroin addicts recovery. Our previous studies demonstrated that 1-THP inhibited heroin self-administration, heroin-induced reinstatement of heroin-seeking behavior in rats, increased the expression of miR-378b and decreased the expression of CB1-Rs, suggesting that 1-THP may attenuate heroin self-administration and heroin-induced reinstatement by regulating the expression of CB1-Rs via miR-378b. This research consistes of three parts. (1) Establishing the models of heroin self-administration and reinstatement of heroin-seeking behavior in rats; (2) Comparing the expression of miR-378b to CB1-Rs mRNA level in neucleus accumbens during heroin reinforcing, extinction and reinstatement with or without the pretreatment with 1-THP; (3) To confirm that CB1-Rs is one of the miR-378b targets by using miR-378b mimic and inhibitor. This study may offer a promising pharmacological target for the intervention of heroin addiction and provide new knowledge with better understanding of the mechanisms of heroin addiction.

海洛因复吸是国际性医学难题，迄今尚未获得满意的防治药物。金国章等人首先报导左旋四氢帕马丁（l-THP）有改善对海洛因渴求的临床效果。此作用引起申请人的极大兴趣，并对l-THP对大鼠海洛因成瘾和复吸行为的影响及其机制进行了初步探索，在前期实验中发现l-THP能抑制大鼠海洛因自身给药及复吸行为，并上调miR-378b的表达，下调其候选靶基因大麻素受体1（CB1-Rs）的表达。由此本课题组设想，l-THP在海洛因成瘾大鼠中通过上调miR-378b，降低CB1-Rs的表达，进而抑制因使用海洛因而过度上升的大麻素系统的功能，从而抑制大鼠海洛因自身给药和复吸行为。为验证上述设想，我们将以miR-378b调控CB1-Rs的表达为切入点，探索l-THP预防海洛因成瘾和复吸的机制。本研究将为l-THP防治海洛因成瘾和复吸的理论研究提供依据，并为海洛因成瘾和复吸的机制研究提供新的实验依据和研究方向。

本课题组通过本项目的研究，共发表论文6篇，其中SCI收录论文3篇。获得国家发明专利授权1项，培养硕士研究生1名。本课题组利用大鼠静脉自身给药系统和自发活动系统，发现左旋四氢帕马丁（l-THP）能在不影响大鼠自发活动的情况下抑制大鼠海洛因自身给药行为和海洛因诱导的海洛因复吸行为。随后本课题组利用µParaflo® miRNA Microarray芯片、Realtime-PCR和Western blot技术发现海洛因自身给药大鼠伏隔核（Nac）中miR-378b下调、CB1-Rs上调，而在l-THP干预海洛因自身给药大鼠Nac中miR-378b上调、CB1-Rs下调。随后利用新生大鼠海马细胞、miR-378b inhibitor和miR-378b mimic，证实miR-378b直接作用于CB1-Rs从而调控其表达。综上所述本课题组证实，l-THP在海洛因成瘾大鼠中通过上调miR-378b，降低CB1-Rs的表达，进而抑制因使用海洛因而过度上升的大麻素系统的功能，从而抑制大鼠海洛因自身给药和复吸行为。