TRANSGENIC MODELS--OPIATE DRUG/OPIOID GENE INTERACTIONS

转基因模型——阿片类药物/阿片类药物基因相互作用

• 批准号: 2120241
• 负责人: MICHAEL J COMB
• 金额: $ 21.31万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-04-01 至 1994-10-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2120241
• 关键词: cell population study; developmental neurobiology; disease /disorder model; drug addiction; drug screening /evaluation; enkephalins; fusion gene; gene expression; genetic promoter element; genetically modified animals; in situ hybridization; laboratory mouse; model design /development; morphine; narcotic antagonists; neuropharmacology; opioid receptor; transcription factor

The addictive properties of opiate drugs are not well understood but have long been postulated to resulted from adaptations in endogenous opioid systems. Agonist induced feedback inhibition of endogenous opioid biosynthesis, as has been reported for monoamine transmitter systems, is a potential mechanism linking drug effects to the expression of endogenous ligands. It has been further suggested that such drug-induced changes in endogenous opioid gene expression may underly manly long-term consequences of opiate addiction including opiate dependence and drug craving which have been particularly difficult to understand at a mechanistic level. In agreement with the above hypothesis, opiate agonists have been reported to decrease proenkephalin mRNA levels in specific brain regions while opiate antagonists have been shown to increase mRNA levels. In addition, opiates are now known to regulate the expression of the immediate early genes, fos and jun, though to be critical regulators of proenkephalin and prodynorphin transcription. This research proposal will investigate transcriptional regulation of endogenous opioid peptides by opiate agonists and antagonists using transgenic animal models. Transgenic mice expressing proenkephalin/LacZ fusion genes have been produced, characterized, and will now be used to analyze the effects of opiate drugs on proenkephalin gene expression in the adult and developing mouse. These animal models will greatly facilitate analysis of proenkephalin expression across the entire nervous system and will detect changes in highly restricted populations of neurons in a fashion previously impossible. Transgenic animals will be used to screen the adult and developing mouse nervous system for cells in which endogenous opioid gene expression is regulated or altered by opiate agonists and antagonists. Most importantly, the transgenic animal system will allow us to analyze the effects of specific DNA elements and transcription factors on regulatory mechanisms coupling drug effects with proenkephalin transcription in an intact nervous system. Regulation will be investigated using knowledge of the promoter region, interacting transcription factors, and second messenger regulation developed over the past 10 years. Proenkephalin/LacZ fusion genes containing mutations within the well characterized cAMP, TPA, and Ca++ inducible enhancer which specifically block the binding of specific transcription factors will allow us to test specific models of trans-synaptic and opiate regulation in an intact nervous system.

阿片类药物的成瘾特性尚未得到很好的理解，但 长期以来一直被认为是内源性阿片样物质适应性的结果， 系统. 激动剂对内源性阿片样物质的反馈抑制 生物合成，如已经报道的单胺递质系统，是一个生物合成的过程。 药物作用与内源性 配体。 还进一步表明，这种药物诱导的变化， 内源性阿片基因表达可能是男性长期后果的基础 鸦片成瘾包括鸦片依赖和药物渴望， 在机械的层面上很难理解。 在 与上述假设一致，据报道阿片激动剂 降低特定脑区的前脑啡肽mRNA水平， 拮抗剂已显示增加mRNA水平。 此外，阿片类药物 现在已知，它们调节即刻早期基因fos的表达， 和jun，虽然是脑啡肽原和强啡肽原的关键调节剂， 转录。 这项研究计划将调查转录 阿片激动剂和拮抗剂对内源性阿片肽的调节 使用转基因动物模型。 转基因小鼠表达 脑啡肽原/LacZ融合基因已经产生，表征，并将 目前已用于分析阿片类药物对前脑啡肽基因的影响 在成年和发育中的小鼠中表达。 这些动物模型将 极大地促进了脑啡肽原在整个细胞中表达的分析， 神经系统，并将检测高度限制人群的变化， 神经元以一种前所未有的方式 转基因动物将 用于筛选成年和发育中的小鼠神经系统中的细胞， 哪些内源性阿片样物质基因的表达受阿片样物质的调节或改变 激动剂和拮抗剂。 最重要的是，转基因动物系统 将使我们能够分析特定DNA元素的影响， 转录因子对药物作用与 脑啡肽原在完整神经系统中的转录。 调控将 使用启动子区域的知识进行研究，相互作用 转录因子和第二信使调节， 近10年 含有突变的脑啡肽原/LacZ融合基因 良好表征的cAMP、TPA和Ca++诱导增强子， 特异性地阻断特定转录因子的结合将允许 我们测试跨突触和阿片调节的特定模型， 完整的神经系统