SP/NK1R系统过度激活参与酒依赖共病焦虑障碍中的机制研究

Substance P (SP) / neurokinin-1 receptor (NK1R) system plays a critical role in comorbidity of alcohol dependence (AD) with anxiety disorders. However, the molecular mechanism is unclear. Our preliminary experiments found that high-anxiety mouse (HAM) group showed a greater alcohol preference and a higher level of NK1R protein in the ventral tegmental area (VTA) than low-anxiety mouse (LAM) group. Moreover, NK1R antagonist attenuated alcohol dependence and reduced anxiety level in both groups. Therefore, we hypothesize that SP/NK1R system is over-activated in HAM after alcohol exposure, showing that SP-ergic neurons in the VTA release more SP and level of NK1R is higher than LAM group; SP subsequently activates NK1R, leading to dopaminergic neurons firing in the VTA; finally, dopaminergic neurons release more DA into the nucleus accumbens, which accelerates the comorbidity of AD with anxiety disorders. The project will make use of 2-bottle-choice ethanol drinking paradigm, stereotactic injection, microdialysis, high performance liquid chromatograph, adeno-associated virus infection, western blot, and immunofluorescence to clarify the molecular mechanism of over-activated SP/NK1R system in comorbidity of AD with anxiety disorders and to examine the potential therapeutic effects of inhibiting the system. The results will reveal a novel clue of understanding AD comorbid with anxiety disorders and provide a new pharmacological target for its treatment.

P物质（SP）/神经激肽1受体（NK1R）系统在酒依赖（AD）共病焦虑障碍中作用关键，但其分子机制不明确。申请人最新研究发现：与低焦虑小鼠相比，高焦虑小鼠对AD的易感性更高，腹侧被盖区（VTA）NK1R活性更强；阻断NK1R后，高、低焦虑小鼠对酒精的依赖被抑制。申请人推测：经过酒精暴露，与低焦虑小鼠相比，高焦虑小鼠SP/NK1R系统过度激活，表现为VTA区SP能神经元释放SP增多，NK1R上调，SP激活突触后膜NK1R，进一步活化VTA 区多巴胺（DA）能神经元，释放DA 到伏隔核，产生更强烈的犒赏效应，促进AD与焦虑障碍共病的发生。本项目将运用双瓶自由选择饮酒、立体定位注射、脑微透析等技术，阐明SP/NK1R系统过度激活导致AD共病焦虑障碍的分子机制，并探讨抑制该系统的潜在治疗作用，以期为AD与焦虑障碍共病机制提供新线索，为其干预提供分子靶点。

SP/NK1R系统在酒依赖共病焦虑障碍中作用关键，但其分子机制不明确。本项目运用高架十字迷宫实验将大鼠分为低焦虑组大鼠和高焦虑组大鼠，利用单瓶饮酒实验建立不同焦虑水平大鼠酒依赖模型，利用酒精戒断综合征评分表对不同焦虑水平酒依赖大鼠进行酒精戒断症状评分，并利用高效液相色谱法测定不同焦虑水平大鼠伏隔核区DA的浓度及腹侧被盖区SP的浓度。通过阻断或激活NK1R受体观察大鼠行为学及分子生学改变。结果发现，低、高焦虑组大鼠均对酒精产生了依赖，停止酒精供应后均表现出戒断症状；但低、高焦虑组大鼠对酒精的偏好未发现统计学意义；与空白对照组相比，低、高焦虑组大鼠伏隔核区的DA浓度及腹侧被盖区的SP浓度均升高。给予NK1R受体拮抗剂处理后，大鼠对酒精的偏好受抑制，伏隔核区DA浓度降低；NK1R受体激动剂处理后，大鼠对酒精的偏好增强，伏隔核区DA浓度升高。本研究发现SP/NKIR系统可能通过调节伏隔核区DA水平参与不同焦虑水平大鼠酒依赖的发生，NK1R可能成为潜在的治疗靶点。