FUNCTIONAL SIGNIFICANCE OF MU OPIOID RECEPTOR TURNOVER

这是一个科学家发展奖（K21）的申请。 的研究 该提案旨在确定μ-阿片样物质 阿片类药物的生化和药理学指标的受体转换 受体功能 阿片受体与肿瘤的关系 阿片受体生物化学和药理学指标占有率 函数对于理解决定 阿片类药物在整个动物中的效力和功效。 初步数据表明 当大鼠脑中μ阿片受体的密度降低时， 通过受体与β-FNA（β-FNA）的烷基化， 海洛因返回前的强化作用 受体结合的恢复。 这些数据表明μ-阿片受体 应使用生化和药理学方法测量周转率 受体功能测定，而不是单独作为指标的受体结合 受体转换的过程。 本研究的目的是确定 用受体结合测定的μ-阿片受体转换的相关性 或受体功能的生物化学测定（腺苷酸环化酶的抑制 和刺激GT3）对μ-阿片样物质激动剂的体内作用的影响。 具体目的1检验了以下假设： 当一个相对小的比例， μ-阿片受体在功能上与G-蛋白偶联。 的时间 β-FNA i. c. v.对μ受体介导的 将比较GT3刺激和腺苷酸环化酶抑制 对吗啡镇痛和过度运动的影响。 的 第二个具体目标是检验μ =阿片受体转换率的假设 在与药理学相关的大脑区域更快， 受体结合实验不能确定这一点， 这些受体群体在那些 在整个大脑中。 将检验这一假设的实验是 与具体目标1中那些类似，除了定量受体 放射自显影术将用于评估μ-阿片受体的密度 在受体烷基化后的离散脑区域中。 第三 特异性目标检验了受体烷基化将导致 药理学相关的受体生物合成的上调 大脑区域。 在受体烷基化后，μ-阿片受体 将在不同时间点在不同脑区域中定量mRNA 并与吗啡的药理作用的恢复进行比较。 具体目的4检验μ-阿片受体抑制 生物合成将最有效地改变药理作用 阿片类药物进入相关的大脑区域。 这些 实验将涉及施用反义寡脱氧核苷酸， μ-阿片受体mRNA进入含有最高量的大脑区域 μ-阿片受体mRNA或其中mRNA增加到 在受体烷基化后的最大程度。

This is a request for a Scientist Development Award (K21). The research in this proposal is designed to determine the relationship of mu-opioid receptor turnover to biochemical and pharmacological indices of opioid receptor function. Investigating the relationship of opioid receptor occupancy with biochemical and pharmacological indices of opioid receptor function is pertinent for understanding the mechanisms that determine the potency and efficacy of opioids in whole animals. Preliminary data suggest that when the density of mu-opioid receptors is decreased in rat brain through receptor alkylation with beta-funaltrexamine (beta-FNA), the reinforcing effects of heroin return prior to the return prior to the return of receptor binding. These data suggest that mu-opioid receptor turnover should be measured using both biochemical and pharmacological assays of receptor function, rather than receptor binding alone as indices of receptor turnover. The objective of this research is to determine the relevance of mu-opioid receptor turnover as measured with receptor binding or biochemical assays of receptor function (inhibition of adenylyl cyclase and stimulation of GTPase) to the in vivo effects of mu-opioid agonists. Specific aim 1 tests the hypothesis that the pharmacological activity of opioids in whole animals is restored when a relatively small proportion of mu-opioid receptors become functionally coupled to G-proteins. The time course of the effects of beta-FNA i.c.v. on mu-receptor-mediated stimulation of GTPase and inhibition of adenylyl cyclase will be compared to the effects on morphine-induced analgesia and hyperlocomotion. The second specific aim tests the hypothesis that mu=opioid receptor turnover is more rapid in pharmacologically-relevant brain regions, and that receptor binding experiments do not determine this due to the fact that these receptor populations represent a relatively small proportion of those in the whole brain. The experiments that will test this hypothesis are similar to those in specific aim 1, except that quantitative receptor autoradiography will be used to assess the density of mu-opioid receptors in discrete brain regions following receptor alkylation. The third specific aim tests the hypothesis that receptor alkylation will result in an upregulation of receptor biosynthesis in pharmacologically-relevant regions of the brain. Following receptor alkylation, mu-opioid receptor mRNA will be quantitated in various brain regions at different time points and compared to the return of the pharmacological effects of morphine. Specific aim 4 tests the hypothesis that inhibition of mu-opioid receptor biosynthesis will be most effective at altering the pharmacological effects of opiates when administered into relevant brain regions. These experiments will involve administering anti-sense oligodeoxynucleotides for mu-opioid receptor mRNA into brain regions that contain the highest amount of mu-opioid receptor mRNA or in which the mRNA is increased to the greatest extent following receptor alkylation.