植物单宁影响布氏田鼠取食行为的神经机制

The plant secondary metabolites (PSM) play an important role in the coevolution of the plants and animals. Tannins are important PSM and they influence the feeding behavior of animals. But there is few about the study of the neural mechanism of the effect of tannins on the feeding behavior. The subjects of this project were there kinds of animals, they were Brandt's voles (Lasiopodomys brandtii) which could select different plants in the filed, Brandt's voles fed on unique plant with different content of tannins or Brandt's voles given different doses of tannin acid through oral, respectively. At first, the feeding behavior of these animals would be observed to confirm the effect of tannins on the feeding behavior. Secondly, in order to study the perception and transduction path of the gustative system to tannins, the change of the anatomic structure of tongue taste buds, the number of gustation cell, the gustation receptors and the signal transduction substance of bitter would be compared among there kinds of animals just mentioned. Thirdly, to explore the effect of tannins on the rewards system, the level of plasmic corticosterone, the content of some neural transmitters and the number of dopamine receptor in ventral tegmental area and nucleus accumbens would be assayed among three kinds of animals. Fourthly, tor probe the effect of tannins on the feeding centre, the plasmic leptin of those animals would be assayed and the expression of some neural peptides, such as orexin, MCH, NPY, POMC and AGRP, would be observed in the hypothalamus of all of the animals mentioned above. Finally, the relationship among the change of feeding behavior and the change of the function of gustation system, rewards system and feeding centre would be analysed to enlucidate the neural mechanism of the influence of tannins on animal feeding behavior. The result of this research would enrich the theory about the coenvolution between plants and animals.

植物次生化合物在动植物的协同进化中发挥着重要作用。单宁是重要的次生化合物，影响动物的取食行为。但单宁影响动物取食行为的神经机制尚无研究。本项目将在口腔给予不同剂量单宁酸后，观察的布氏田鼠的取食行为，确定单宁对布氏田鼠取食行为的影响；测定其血液中皮质酮含量、中脑腹侧被盖区及伏膈核等部位各类神经递质含量和多巴胺结合受体数目，确定单宁对动物奖赏系统的影响；测定血液中瘦素水平和下丘脑MCH、Orexin、POMC、AGRP及NPY等神经肽的表达，确定单宁对动物摄食中枢的作用。通过奖赏系统及摄食中枢功能与取食行为间的相关性分析，揭示单宁影响动物取食行为的神经机制，为动植物间的协同进化提供理论依据。

本项目通过测定布氏田鼠血液瘦素水平和下丘脑MCH、Orexin、POMC、AGRP及NPY等神经肽的表达，确定单宁对摄食中枢的作用；测定布氏田鼠前额皮层、中脑腹侧被盖区及伏膈核等部位多巴胺结合受体数目的变化，确定单宁对奖赏系统的影响；以此揭示单宁影响动物取食行为的神经机制，为动植物间的协同进化提供新的理论依据。.项目已按计划完成研究内容，达到研究目标。.主要研究结果如下：.单宁酸在较短的时间内能抑制布氏田鼠的取食，而随着处理时间的增加，布氏田鼠又会以增加取食为对策来抵御单宁酸造成的影响；虽然在长时间单宁酸处理后，脂肪囤积量在逐渐下降，但布氏田鼠通过调节能量平衡来维持体重保持不变。.单宁酸抑制雌雄布氏田鼠pp-MCH基因mRNA转录和蛋白表达以及受体MCHR1基因的转录。但对pp-Orexin的影响比较复杂，这种基因及其受体的表达表现出性分化现象。单宁酸也可通过增加下丘脑弓状核POMC并降低NPY及AgRP基因和蛋白水平的表达来调控布氏田鼠的取食行为。因此，单宁酸可以通过影响下丘脑相关食欲神经肽的表达来调控布氏田鼠的食欲及取食行为。.但单宁酸对布氏田鼠血清瘦素水平无显著影响。各剂量单宁酸对于雌雄布氏田鼠下丘脑弓状核OB-Rb的表达也无显著影响。说明单宁酸对布氏田鼠取食行为的影响不通过瘦素及其受体。.对奖赏系统的研究表明，短期和长期用单宁酸处理，会降低布氏田鼠前额皮层区的DRD2（多巴胺能Ⅱ型受体）mRNA水平，短期单宁酸处理增加杏仁核和中脑腹侧被盖区的DRD2mRNA水平。说明单宁酸会通过影响奖赏系统来影响布氏田鼠的取食行为。.项目进行期间：共发表论文3篇，1篇为中文CSCD收录文章，2篇为SCI收录文章。培养硕士研究生5名，博士生1名。