NICOTINE EFFECTS ON THE ADRENAL MEDULLA AND BRAIN

尼古丁对肾上腺髓质和大脑的影响

基本信息

批准号：
2654347
负责人：
ARNOLD WILLIAM Tank
金额：
$ 22.1万
依托单位：
UNIVERSITY OF ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
1990
资助国家：
美国
起止时间：
1990-05-01 至 2000-09-29
项目状态：
已结题

项目摘要

The intake of nicotine results in dramatic increases in the release and biosynthesis of catecholamines in the adrenal medulla, sympathetic ganglia and brain. The effects of nicotine on peripheral catecholaminergic systems are responsible for many of the pharmacological actions of the drug on the cardiovascular system, while its effects on brain catecholaminergic systems may participate in mediating some of the addictive properties of the drug. Catecholamine biosynthesis in both periphery and brain is controlled primarily by the activity of tyrosine hydroxylase. The studies outlined in this proposal test a number of hypotheses concerning the mechanisms by which nicotine regulates tyrosine hydroxylase gene expression in the periphery (the adrenal medulla) and in brain (locus coeruleus, substantia nigra and ventral tegmental area). The specific aims are as follows: (1) to test the hypothesis that the effect of systemically-administered nicotine on TH gene expression in the adrenal medulla is partially due to transsynaptic mechanisms initiated in the brain; (2) to test whether nicotine induces TH and Th-mRNA in the brain by interaction with brain nicotinic receptors; (3) to test whether specific DNA response elements within the TH gene 5' flanking region mediate the stimulation of the gene in vivo after nicotine administration in transgenic mice; and (4) to identify members of the c-jun/c-fos and CREB/ATF family of transcription factors that are involved in the regulation of the Th gene in intact cells. Animals will be treated with nicotine and other drugs using different routes of administration and effects on TH activity, TH protein and TH-mRNA will be monitored in adrenal and brain. TH gene transcription rate will be measured in adrenal medulla. Transgenic mice that express a transgene containing wild type or mutagenized TH gene 5' flanking region fused to a reporter gene will be administered nicotine and the effects of the drug on reporter gene and endogenous TH gene expression will be monitored. PC12 cells will be used as a model system to test which transcription factors participate in the regulation of the TH gene in the intact cells. Antisense DNA, antisense RNA or dominant negative mutants will be used to "knock-out" specific transcription factors in these experiments. These studies will increase our understanding of the mechanisms responsible for nicotine's effects on the cardiovascular system and will open up new avenues to study the mechanisms by which nicotine produces physical dependence, withdrawal and other aspects of addiction.

尼古丁的摄入会导致尼古丁的释放和释放急剧增加肾上腺髓质、交感神经节中儿茶酚胺的生物合成和大脑。尼古丁对外周儿茶酚胺能系统的影响负责药物对人体的许多药理作用心血管系统，同时对大脑儿茶酚胺能的影响系统可能会参与调节某些令人上瘾的特性药物。儿茶酚胺在外周和大脑中的生物合成主要由酪氨酸羟化酶的活性控制。研究本提案中概述的测试了一些有关尼古丁调节酪氨酸羟化酶基因的机制在外周（肾上腺髓质）和大脑（位点）中表达蓝斑、黑质和腹侧被盖区）。具体目标如下： (1) 检验假设全身施用尼古丁对肾上腺 TH 基因表达的影响髓质部分是由于在髓质中启动的跨突触机制脑; (2) 测试尼古丁是否诱导大脑中的TH和Th-mRNA 与大脑烟碱受体相互作用； (3) 测试是否具体 TH 基因 5' 侧翼区域内的 DNA 反应元件介导尼古丁注射后体内基因的刺激转基因小鼠； (4) 确定 c-jun/c-fos 成员， CREB/ATF 转录因子家族参与完整细胞中 Th 基因的调节。动物将受到治疗尼古丁和其他药物使用不同的给药途径和对 TH 活性、TH 蛋白和 TH-mRNA 的影响将在肾上腺和大脑。 TH基因转录率将在肾上腺中测量髓质。表达含有野生型或与报告基因融合的突变 TH 基因 5' 侧翼区域将是给予尼古丁以及该药物对报告基因的影响将监测内源性 TH 基因表达。将使用PC12细胞作为测试哪些转录因子参与的模型系统完整细胞中 TH 基因的调节。反义DNA、反义 RNA或显性失活突变体将被用来“敲除”特定的这些实验中的转录因子。这些研究将会增加我们对尼古丁影响机制的理解心血管系统，并将开辟新的研究途径尼古丁产生身体依赖、戒断和戒断的机制成瘾的其他方面。