Neural Actions of Toluene

甲苯的神经作用

• 批准号: 6625672
• 负责人: JOHN J. WOODWARD
• 金额: $ 28.79万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-15 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6625672
• 关键词: G protein; GABA receptor; NMDA receptors; acetylcholine; binding sites; cell line; egg /ovum; ethanol; hippocampus; inhalation drug abuse; membrane channels; neural transmission; neurons; receptor; receptor binding; solvents; tissue /cell culture; toluene; voltage /patch clamp

DESCRIPTION (provided by applicant): Volatile solvents such as toluene, benzene and trichloroethane are widely distributed in a variety of products encountered in both industrial and home settings. These include glues, thinners, rubber cements, aerosol sprays, nail polish removers, correction fluid and dry cleaning solvents. Although the occupational hazards of exposure to these solvents have been previously examined in a variety of toxicological studies, the cellular and molecular sites of action that account for their intoxicating effects are virtually unknown. Surveys of drug use show that a significant percentage of the population has used volatile solvents for their intoxicating properties and such use is especially prevalent among adolescents and teens who may have easy access to these products. Previous behavioral studies show that toluene and other abused volatile solvents display actions similar to that observed for CNS depressants such as ethanol, barbiturates, benzodiazepines, and anesthetics. Thus, we hypothesize that abused solvents, like other CNS depressants, may exert some of its neurobehavioral effects by altering the function of specific ion channels that are involved in mediating and modulating neuronal transmission. We have generated data to support this hypothesis and have demonstrated that toluene and other volatile solvents inhibit the function of recombinant and native NMDA and acetylcholine receptors expressed in oocytes and cultured neurons. This inhibition was dose-dependent and was influenced by the subunit composition expressed. In contrast to ethanol, toluene had negligible effects on currents mediated by non-NMDA receptors or on G-protein coupled potassium channels. These results suggest that abused solvents may show greater selectivity than alcohol with respect to their ability to modulate the activity of neuronal ion channels. Studies outlined in this proposal will test this hypothesis by determining the sensitivity of recombinant and native ion channels to toluene and other volatile solvents that are subject to abuse. Two-electrode voltage-clamp and patch-clamp electrophysiology will be used to analyze the solvent sensitivity of recombinant ionotropic receptors expressed in oocytes and HEK cells. The molecular sites of action for toluene will be explored by testing whether sites known to regulate the alcohol/anesthetic sensitivity of these channels also regulate solvent sensitivity. Finally, the relevance of the findings obtained in recombinant receptor systems will be assessed by measuring the effects of toluene and other abused solvents on ion channels expressed in cultured brain neurons using whole-cell patch clamp and calcium imaging. Results obtained from these studies outlined are expected to greatly expand our knowledge of the cellular and molecular targets of these important drugs of abuse.

描述（由申请人提供）：挥发性溶剂，如甲苯、苯 和三氯乙烷广泛分布在各种产品中遇到 在工业和家庭环境中。包括胶水，稀释剂，橡胶 粘固剂、喷雾剂、指甲油去除剂、修正液和干燥剂 清洁溶剂。虽然接触这些物质的职业危害 以前已经在各种毒理学研究中检查了溶剂， 细胞和分子的作用部位， 影响几乎是未知的。毒品使用调查显示， 10%的人使用挥发性溶剂进行麻醉 这种使用在青少年和青少年中特别普遍， 可以很容易地获得这些产品。先前的行为研究表明， 甲苯和其他滥用的挥发性溶剂显示类似的作用， 观察到中枢神经系统抑制剂，如乙醇，巴比妥类，苯二氮卓类， 和麻醉剂。因此，我们假设，滥用溶剂，像其他中枢神经系统 抑制剂，可能会发挥其一些神经行为的影响，通过改变 参与介导和调节的特定离子通道的功能 神经传递我们已经生成了支持这一假设的数据， 已经证明甲苯和其他挥发性溶剂抑制了该功能 重组和天然NMDA和乙酰胆碱受体在卵母细胞中表达 和培养的神经元。这种抑制是剂量依赖性的，并受到 表达的亚基组成。与乙醇相比，甲苯具有 对非NMDA受体介导的电流或G蛋白的影响可忽略不计 偶联钾离子通道这些结果表明，滥用溶剂可能会显示 就其调节蛋白质的能力而言， 神经元离子通道的活性。本提案中概述的研究将测试 通过确定重组和天然离子的灵敏度， 甲苯和其他易挥发溶剂的通道，容易被滥用。 将使用双电极电压钳和膜片钳电生理学， 分析表达的重组离子型受体的溶剂敏感性 在卵母细胞和HEK细胞中。甲苯的分子作用位点将是 通过测试已知调节酒精/麻醉剂的部位 这些通道的敏感性也调节溶剂敏感性。最后 在重组受体系统中获得的发现的相关性将是 通过测量甲苯和其他滥用溶剂对离子的影响进行评估 使用全细胞膜片钳技术在培养的脑神经元中表达通道， 钙显像从这些概述的研究中获得的结果预计 大大扩展了我们对这些细胞和分子靶点的了解， 滥用的重要药物。