NICOTINE MEDIATED SODIUM FLUX IN PRIMARY CULTURES

原代培养物中尼古丁介导的钠通量

基本信息

批准号：
3424098
负责人：
Barbara J Morley
金额：
$ 7.16万
依托单位：
FATHER FLANAGAN'S BOYS' HOME
依托单位国家：
美国
项目类别：
财政年份：
1991
资助国家：
美国
起止时间：
1991-03-01 至 1993-10-31
项目状态：
已结题

项目摘要

Eighty percent of smokers who quit relapse within a year. Although there are many reasons for relapse, the active ingredient in cigarettes, nicotine, has properties of an addictive substance. All of the actions of nicotine are not known, but nicotine is known to act as receptor sites in nervous tissues. Its action at acetylcholine receptor sites may be related to its addictive properties. The nicotinic acetylcholine receptors in mammalian brain have not been well-characterized. Nicotine binds with high affinity (Kd 1-10 nM) to at least one population of brain nicotinic receptors. The high-affinity binding to brain tissue is a paradox. Electrophysiological studies suggest that micromolar concentrations of nicotine are necessary for receptor activation. It has been suggested that the brain receptors are desensitized during the assay procedure (in which 10-20 nM concentrations of nicotine are used), indicating a 1000-fold difference between the K-activation (K- act) and K-desensitization (K-des) of nicotinic receptors in mammalian brain. Previous work in our laboratory indicates that the K-act and K-des of PC12 cells, which possess a well-characterized neuronal receptor, are 7.7 X 10(5) M and 8.2 X 10(5) M, respectively. On the basis of these data, we question whether the K-des and K-act in brain tissue would differ by 3 orders of magnitude. This question cannot be resolved using brain tissue in vivo. We therefore propose to study this question in primary neuronal brain cultures using 22Na+ influx. 22Na+ influx has not previously been demonstrated in primary neuronal cultures derived from mammalian brain. Therefore, the goal of this research is to demonstrate nicotinic receptor mediated 22Na" influx in mammalian brain culture. Experiments using 22Na+ influx and nicotine and cytisine as agonists will be performed to determine the K-act and K-des of the receptors. Influx will be also carried out in the presence of nicotinic antagonists. These experiments will serve as the basis for future inves- tigations of the physiological properties of brain nicotinic receptors.

在一年内退出复发的吸烟者中有80％。虽然那里是复发的许多原因，是香烟中的活性成分，尼古丁具有成瘾性物质的特性。所有的行动尼古丁尚不清楚，但尼古丁被称为受体位点神经组织。它在乙酰胆碱受体位点的作用可能是相关的具有上瘾的特性。哺乳动物大脑中的烟碱乙酰胆碱受体尚未是特殊的。尼古丁与高亲和力结合（KD 1-10 nm）与AT结合至少一个脑烟碱受体人群。高亲和力与脑组织的结合是悖论。电生理研究表明尼古丁的微摩尔浓度是受体所必需的激活。有人建议大脑受体脱敏在测定过程中（其中10-20 nm的尼古丁浓度使用），表明k激活之间有1000倍的差异（k- 哺乳动物中烟碱受体的ACT）和K-敏感性（K-DES）脑。我们实验室的先前工作表明PC12的K-ACT和K-DES 具有良好特征神经元受体的细胞为7.7 x 10（5）m和8.2 x 10（5）m。根据这些数据，我们疑问脑组织中的K-DES和K-ACT是否会差异3 数量级。这个问题无法使用脑组织解决体内。因此，我们建议在原发性神经元中研究这个问题使用22NA+涌入的脑培养。 22NA+流入以前尚未在原发性神经元中证明源自哺乳动物大脑的培养物。因此，这项研究的目标是要证明烟碱受体介导的22Na“哺乳动物的流入脑文化。使用22NA+流入，尼古丁和氰胺作为实验AS 将进行激动剂以确定k-act和k-des 受体。在烟碱存在的情况下，涌入也将进行对手。这些实验将作为未来投入的基础脑烟碱受体的生理特性的兴趣。