METHAMPHETAMINE AND GDNF/BDNF IN AGED DOPAMINE SYSTEMS

项目0002中的拟议实验将评估DA系统挑战对这些系统随老化过程自然衰退的影响。胶质细胞源性神经营养因子（GDNF+/-）或脑源性神经营养因子（BDNF+/-）通过基因缺失和甲基苯丙胺（METH）暴露的减少都产生DA神经系统结构和/或功能的长期改变。一般的工作假设 提出的实验是，重复METH与GDNF或BDNF减少的相互作用将加剧伴随衰老过程的DA系统的结构和功能变化。为了检验这一假设，将在3、12、18和24月龄时检查在年轻成年时暴露于METH的雄性和雌性GDNF+/-或BDNF+/-小鼠。将使用两种策略检查这些治疗组合对DA系统的影响：（1）免疫细胞化学染色程序将用于评估DA和中型多棘纹状体神经元的完整性以及抗炎药米诺环素是否将阻断METH毒性，（2）基因表达实验随后通过免疫印迹法评估相关蛋白质将用于鉴定DA神经元功能特性的变化。这些实验的结果将与项目0003中描述的小胶质细胞实验以及DAT和VMAT 2整合。 评估项目0004，以提供有关一些可能的遗传和环境因素如何可能有助于在老龄化人口中注意到的DA功能下降的不同速度的信息。这些研究的意义在于，它们将确定遗传易感因子（GDNF或BDNF）的突变与常见的环境损伤（METH）相结合是否会加剧与年龄相关的多巴胺系统下降。这项研究有可能确定相关的基因和蛋白质，可以操纵 并在将来重新引入模型中，以减弱多次损伤对衰老期间多巴胺神经元功能下降的影响。

The proposed experiments in Project 0002 will assess the impact of challenges to DA systems on the natural decline of these systems that accompany the aging process. Reductions in glial cell derived neurotrophic factor (GDNF+/-) or brain-derived neurotrophic factor (BDNF+/-) via gene deletion and methamphetamine (METH) exposure all produce long-term alterations in DA neural system structure and/or function. The general working hypothesis for the proposed experiments is that the interaction of repeated METH with either GDNF or BDNF reduction will exacerbate the structural and functional changes of DA systems that accompany the aging process. To test this hypothesis, male and female GDNF+/- or BDNF+/- mice exposed to METH as young adults will be examined at 3, 12, 18, and 24 months of age. Effects of these treatment combinations on DA systems will be examined using two strategies: (1) Immunocytochemical staining procedures will be used to assess the integrity of DA and medium spiny striatal neurons and whether the anti-inflammatory drug, minocycline, will block METH toxicity, (2) gene expression experiments (Affymetrix GeneChips and in situ hybridization) followed by the assessment of relevant proteins by immunoblotting will be used to identify changes in the functional properties of the DA neurons. The results of these experiments will integrate with the microglia experiments described in Project 0003 and the DAT and VMAT2 evaluations of Project 0004 to provide information about how some likely genetic and environmental factors might contribute to the different rates of declining DA function noted in the aging population. The significance of these studies is that they will determine whether a mutation in a genetic susceptibility factor (either GDNF or BDNF) combined with a commonly encountered environmental insult (METH) exacerbates the age-related decline of the dopamine systems. This investigation has the potential to identify associated genes and proteins that can be manipulated and re-introduced into the model in the future in order to attenuate the impact of multiple insults on the decline of dopamine neuronal function during aging.