Neural Actions of Toluene

甲苯的神经作用

基本信息

批准号：
7024517
负责人：
JOHN J. WOODWARD
金额：
$ 28.06万
依托单位：
MEDICAL UNIVERSITY OF SOUTH CAROLINA
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-04-15 至 2009-02-28
项目状态：
已结题

项目摘要

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，例如甲苯，苯和三氯乙烷广泛分布在各种产品中在工业和家庭环境中。这些包括胶水，稀释剂，橡胶水泥，气溶胶喷雾剂，指甲油去除剂，校正液和干燥清洁溶剂。虽然暴露于这些的职业危害以前在多种毒理学研究中检查了溶剂，细胞和分子的作用位置，以造成陶醉效果几乎是未知的。吸毒的调查表明，重要的人口百分比已使用挥发性溶剂进行醉酒在青少年和青少年中，财产和这种使用尤其普遍可能可以轻松访问这些产品。以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动作观察到CNS抑郁剂，例如乙醇，巴比妥酸盐，苯二氮卓类药物，和麻醉药。因此，我们假设像其他CN一样滥用溶剂抑郁剂可能会通过改变其某些神经行为影响参与介导和调节的特定离子通道的功能神经元传输。我们已经生成了数据来支持这一假设和已经证明甲苯和其他挥发性溶剂抑制了功能在卵母细胞中表达的重组和天然NMDA和乙酰胆碱受体的和培养的神经元。这种抑制是剂量依赖性的，受表达的亚基组成。与乙醇相反，甲苯对非NMDA受体介导的电流或G蛋白介导的电流的影响可忽略不计耦合的钾通道。这些结果表明滥用溶剂可能显示相比酒精对调节能力的选择性更高神经离子通道的活性。该提案中概述的研究将测试通过确定重组和天然离子的敏感性来假设甲苯和其他挥发性溶剂的渠道。两电极电压钳和斑板钳电生理学将用于分析表达的重组离子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是否已知用于调节酒精/麻醉的站点来探索这些通道的灵敏度还调节溶剂灵敏度。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斑块夹在培养的脑神经元中表达的通道，钙成像。从这些研究中获得的结果有望大大扩展了我们对这些细胞和分子靶标的知识重要的虐待药物。