海洛因依赖大鼠VTA、NAc、PFC区DA、GABA神经元μ、δ、κ阿片受体及CREB表达的研究

Heroin addiction has become a worldwide public hazard.The mechanisms underlying this dependence still need more in-depth investigations. Many studies have demonstrated that ventral tegmental area (VTA),nucleus accumbens (NAc), and prefrontal cortex(PFC), which are mainly rich of dopamine( DA) and γ-aminobutyric acid (GABA) neurons, are the key structures related to drug dependence. Opioid receptors were found to be the initiation site of opioid-induced reward. In addition, cAMP response element-binding (CREB) has been shown to be a critical factor during the process of drug dependence. However,no study has reported the expression of opioid receptors(μ、δ、κ) and CREB in DA and GABA nuerons in the VTA,NAc, and PFC regions during the process of heroin addiction.The relationships of these substances are also unclear.The aim of this study was to locate DA and GABA nerons in VTA,NAc,and PFC regions of addict rat brains and to investigate the expression of opioid receptors and CREB in DA and GABA nerons. Both acute and chronic heroin dependence rat models and CPP models were developed.Immunohistochemistry, in situ hybridization, electron microscopy, western blot, and RT-PCR techniques were conducted. Agonists/antagonists of opioid receptors were used to examine expression changes and their relationships. Our studies help further explore the central mechanisms of heroin dependence and provide experimental and theoretical basis for clinical treatment of heroin addicts.

海洛因依赖已成为世界公害，其依赖机理正纵深研究。中脑腹侧被盖区（VTA）、伏隔核（NAc）和前额叶皮质（PFC）是药物依赖的重要部位，该部位主要为多巴胺（DA）和γ-氨基丁酸（GABA）能神经元。阿片受体是阿片类药物发挥奖赏的起始位点。CREB是药物依赖过程中的一种关键因子。但迄今在海洛因依赖过程中VTA、NAc、PFC区DA、GABA神经元有无μ、δ、κ阿片受体和CREB表达及其相互关系未见报道。本研究拟通过海洛因急慢性给药和CPP模型，用免疫组化、原位杂交、电镜、Western blot、RT-PCR等技术，观察依赖大鼠VTA、NAc、PFC区DA、GABA神经元的定位；进而观察该两种神经元有无μ、δ、κ阿片受体和CREB表达及其变化；并分别使用相应受体激动剂、拮抗剂观察表达的改变及其相互关系。进一步揭示海洛因依赖的中枢机制，为解除依赖提供实验和理论依据，为治疗提供可能的途径。

海洛因成瘾是一种反复发作的脑损伤疾病，中脑腹侧被盖区（VTA）、伏隔核（NAc）和前额叶皮质（PFC）是成瘾的重要部位，该部位主要为多巴胺（DA）能神经元。DA神经元中阿片受体、cAMP-PKA-CREB信号通路、△FosB、神经营养因子家族和SIRT家族在药物成瘾时的表达变化以及和酪氨酸羟化酶(TH)、多巴胺-β-羟化酶（DβH）、多巴胺受体（DRD）及多巴胺转运体（DAT）之间的关系尚未阐明清楚。本课题通过大鼠海洛因急慢性给药、戒断和条件位置偏爱（CPP）模型，用免疫组化、电镜、基因芯片、高通量测定、Western blot、RT-PCR 等技术，对VTA、NAc和PFC中DA能神经元的μ、δ、κ阿片受体、cAMP-PKA-CREB信号通路、神经营养因子家族和SIRT家族在海洛因成瘾、戒断的表达变化进行了研究。之后利用病毒转染技术、融合蛋白技术调节脑源性神经营养因子（BDNF）和SIRT1在NAc的表达水平，观察对大鼠戒断症状和CPP的影响。结果表明，μ、κ阿片受体、cAMP-PKA-CREB信号通路、神经营养因子家族和SIRT家族均参与了对海洛因成瘾的调节，上调BDNF能减轻成瘾大鼠戒断症状，此外BDNF上调和沉默SIRT1均降低了成瘾大鼠的CPP行为。本课题研究结果进一步揭示了海洛因成瘾的中枢机制，为解除成瘾提供实验和理论依据，为治疗提供可能的途径。