TRANSGENIC MODELS--OPIATE DRUG/OPIOID GENE INTERACTIONS

鸦片类药物的成瘾特性还不是很清楚，但已经有了 长期以来一直被认为是内源性阿片类药物适应的结果 系统。激动剂对内源性阿片类药物的反馈抑制作用 据报道，单胺类递质系统的生物合成是一种 药物作用与内源性神经营养因子表达的可能机制 配基。有人进一步指出，这种由药物引起的变化 内源性阿片基因表达可能会导致长期的不良后果 阿片成瘾，包括阿片依赖和药物渴求 在机械层面上尤其难以理解。在……里面 与上述假设一致，阿片类激动剂已被报道为 阿片类药物降低特定脑区前脑啡肽基因表达 已有研究表明，拮抗剂可以提高信使核糖核酸水平。此外，鸦片类药物 现已知可调节即刻早期基因FOS的表达 和Jun，虽然是前脑啡肽和前强啡肽的关键调节者 抄写。这项研究提案将调查转录 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 原脑啡肽/LacZ融合基因已经产生、鉴定并将 现用于分析阿片类药物对脑啡肽原基因的影响 在成年和发育中的小鼠中的表达。这些动物模型将 极大地方便了对整个脑啡肽原表达的分析 并将检测高度受限制的人群的变化 以一种以前不可能实现的方式。转基因动物将成为 用于筛选成年和发育中的小鼠神经系统中的细胞 阿片类药物对内源性阿片基因表达的调节或改变 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元素和 转录因子在药物作用与调控机制中的作用 原脑啡肽原在完整神经系统中的转录。监管将会 利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在 过去的10年里。含有突变的前脑啡肽/lacZ融合基因 特性良好的cAMP、TPA和钙诱导增强子 明确地阻断特定转录因子的结合将允许 美国将测试跨突触和阿片类药物调节的特定模型 完整的神经系统。

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.