EFFECTS OF NICOTINE ON THE ADRENAL MEDULLA

尼古丁对肾上腺髓质的影响

• 批准号: 2117385
• 负责人: ARNOLD WILLIAM Tank
• 金额: $ 15.34万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-05-01 至 1994-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2117385
• 关键词: EFFECTS; NICOTINE; ADRENAL; MEDULLA

The intake of nicotine results in the elevation of blood catecholamine levels, which is associated with increases in heart rate and blood pressure in humans and experimental animals. This increase in blood catecholamines is due partially to the nicotine-mediated increase in catecholamine secretion from the adrenal medulla. In order to prevent the depletion of the cellular stores of catecholamines during these periods of enhanced secretion, catecholamine biosynthesis is enhanced via the activation and induction of tyrosine hydroxylase (TH). The studies outlined in this proposal are designed to investigate the pharmacological and intracellular molecular mechanisms by which nicotine regulates TH in the rat adrenal medulla. The specific aims of the proposal are as follow: (1) to characterize pharmacologically the nicotine-mediated activation of TH and induction of TH-mRNA that occur in the adrenal medulla of rats treated with nicotine; (2) to determine whether the nicotine-mediated induction of adrenal TH-mRNA is due to the stimulation of the transcription rate of the TH gene; (3) to identify rat adrenomedullary nuclear proteins that interact with the 5'flanking region of the TH gene and that may be involved in the activation of the gene by nicotine; and (4) to determine whether tolerance develops to the nicotine-mediated activation of adrenal TH in chronically- treated rats. TH-mRNA levels will be measured by hybridization to a cloned cDNA probe. The transcription rate of the TH gene will be measured using a specific and sensitive nuclear run-on assay developed in my laboratory. Nuclear proteins that bind to he promoter regions of the TH gene will be measured by a gel shift assay using end-labeled restriction fragments isolated from a genomic clone that codes for the TH gene. THese measurements will be made using either control rats treated with saline or rats treated acutely or chronically for different periods of time and by different routes of administration with nicotine. These studies will increase our understanding of the mechanisms responsible for the regulation of adrenal TH by nicotine and thus, will shed light on the mechanisms by which nicotine elevates blood catecholamines and elicits the consequent cardiovascular effects of the drug.

尼古丁的摄入导致血中儿茶酚胺的升高 水平，这与心率和血压的增加有关 在人类和实验动物中。 血液中的儿茶酚胺增加 部分是由于尼古丁介导的儿茶酚胺增加 肾上腺髓质的分泌物。 为了防止消耗 在这些增强的时期， 分泌，通过激活和增强儿茶酚胺的生物合成， 酪氨酸羟化酶（TH）诱导。 本文中概述的研究 建议旨在研究药理学和细胞内 尼古丁调节大鼠肾上腺TH的分子机制 髓质 建议的具体目标如下：（1） 表征烟碱介导的TH活化， 诱导TH-mRNA的发生在大鼠肾上腺髓质处理 尼古丁;（2）确定尼古丁介导的 肾上腺TH-mRNA的表达是由于刺激了 TH基因;（3）鉴定大鼠肾上腺髓质细胞核中与TH基因相互作用的蛋白 与TH基因的5 '侧翼区，并可能参与 尼古丁对基因的激活;以及（4）确定耐受性是否 在慢性- 治疗的老鼠 TH-mRNA水平将通过与克隆的 cDNA探针。 TH基因的转录速率将使用 在我的实验室开发的特异性和敏感性的核运行分析。 与TH基因启动子区结合的核蛋白将被 通过使用末端标记的限制性片段的凝胶迁移测定来测量 分离自编码TH基因的基因组克隆。 这些 使用盐水处理的对照大鼠或 大鼠急性或慢性治疗不同的时间段，并通过 尼古丁的不同给药途径。 这些研究将 增加我们对监管机制的了解 肾上腺TH的尼古丁，因此，将阐明的机制， 尼古丁会升高血液中的儿茶酚胺， 药物的心血管效应。