NICOTINE EFFECTS ON THE ADRENAL MEDULLA AND BRAIN

尼古丁的摄入会导致尼古丁的释放急剧增加， 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 负责药物的许多药理作用， 心血管系统，而其对脑儿茶酚胺能 系统可能参与介导的一些上瘾的性质， 流毒外周和大脑中的儿茶酚胺生物合成是 主要由酪氨酸羟化酶的活性控制。研究 本提案中概述了一些关于 尼古丁调节酪氨酸羟化酶基因的机制 表达在外周（肾上腺髓质）和脑（位点 蓝斑、黑质和腹侧被盖区）。具体目标 具体如下：（1）检验假设， 全身给予尼古丁对肾上腺TH基因表达的影响 部分是由于在延髓中启动的跨突触机制， （2）通过测定尼古丁是否诱导脑中TH和Th-mRNA的表达， 与脑烟碱受体的相互作用;（3）测试是否特异性 TH基因5'侧翼区内的DNA应答元件介导 尼古丁给药后体内基因的刺激 转基因小鼠;和（4）鉴定c-jun/c-fos的成员， CREB/ATF转录因子家族参与了 完整细胞中Th基因的调节。动物将接受以下处理： 尼古丁和其他药物使用不同的给药途径， 对TH活性、TH蛋白和TH-mRNA的影响将在 肾上腺和大脑将在肾上腺中测量TH基因转录率 髓质表达含有野生型或野生型转基因的转基因小鼠 与报道基因融合的诱变的TH基因5'侧翼区将被 给予尼古丁和药物对报告基因的影响， 将监测内源性TH基因表达。将使用PC 12细胞 作为一个模型系统来测试哪些转录因子参与了 完整细胞中TH基因的调节。反义DNA RNA或显性失活突变体将被用于“敲除”特异性 这些实验中的转录因子。这些研究将增加 我们对尼古丁作用机制的理解 心血管系统，并将开辟新的途径，研究 尼古丁产生身体依赖、戒断和 成瘾的其他方面。

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.