Distribution of Exposed Organic Solvent in the Brain and its Effect on GABA_A Receptor

暴露有机溶剂在脑内的分布及其对GABA_A受体的影响

• 批准号: 12670356
• 负责人: ITO Takehiko
• 金额: $ 1.66万
• 依托单位: OKAYAMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12670356/
• 关键词: organic solvent intoxication; m-xylene; GABA recptors; autoradiography; inhalation experiments; industrial health; Ro15-4513; ベンゾジアゼピン結合部位

1. Establishment of a new system for exposing organic solvents to small animalsA system suitable for exposing m-xylene to rats was made, and a series of experiments was conducted using this system. The exposure system was easy to handle, and was useful.2. Effects of m-xylene exposure on GABA_A receptor in the brainAutoradiographic study was done using three ligands specific to GABA_A receptors. Autoradiography using [^<35>S]t-butylbicyclophosphorothionate revealed a significant increase in the binding in the cerebellum, whereas that using [^3H]flunitrazepam showed no significant changes. To further investigate the possibility of a receptor subunit-specific effect of m-xylene, autoradiogram using [^3H]Ro15-4513 was obtained. Significant changes in binding were found in the II-IIIth layer of the cerebral cortex, CA1, Inferior colliculus and in the granule cells of the cerebellum. The increase in the binding in the granule cells seemed to be a subunit-specific change, possibly due to alteration in alpha6 subunit-containing receptors.3. Measurement of m-xylene concentration in several areas of the brainThe levels of m-xylene on and after the exposure were measured, and referenced with its metabolite concentration in urine.4. Measurement of m-methylhippuric acid in urine on and after the exposureThe levels of m-methylhippuric acid were measured on and after the exposure. While m-xylene level and m-methylhippuric acid level paralleled during the exposure, the two levels decreased in a different manner after the exposure.These findings taken together, the basic data to develop a new biological effect monitoring of m-xylene were obtained. The new biological monitoring method will use changes in GABA_A receptor as indices of biological effect, and metabolite of m-xylene in urine (m-methylhippuric acid and/or its precursor m-tolualdehyde) as indices of the exposure, respectively.

1.建立了一种适合于大鼠接触间二甲苯的实验系统，并进行了一系列实验。曝光系统操作简单，实用性强.间二甲苯暴露对脑内GABA_A受体的影响用GABA_A受体特异性配体进行放射自显影研究。使用[^<35>S]叔丁基双环硫代磷酸酯的放射自显影显示小脑中的结合显著增加，而使用[^3H]氟硝西泮的放射自显影显示无显著变化。为了进一步研究间二甲苯的受体亚基特异性效应的可能性，使用[^3H] Ro 15 -4513获得了放射自显影图。在大脑皮层的第II-III层、CA 1、下丘和小脑的颗粒细胞中发现了结合的显著变化。颗粒细胞中结合的增加似乎是亚单位特异性的变化，可能是由于含有α 6亚单位的受体的改变。间二甲苯在脑内不同区域浓度的测定在暴露后及暴露后测定间二甲苯的浓度，并与尿中代谢产物的浓度相对照.暴露时和暴露后尿中间甲基马尿酸的测定在暴露时和暴露后测定间甲基马尿酸的水平。间二甲苯和间甲基马尿酸在暴露过程中呈上升趋势，暴露后呈不同的下降趋势，为建立间二甲苯生物效应监测方法提供了基础数据。新的生物监测方法将分别以GABA_A受体的变化作为生物效应指标，以尿中间二甲苯代谢产物（间甲基马尿酸和/或其前体间甲苯甲醛）作为暴露指标。

项目成果

Ito, T., Yoshitome, K., Horike, T. and Kira S.: "Distribution of inhaled m-xylene in rat brain and its effect on GABA_A receptor binding"Journal of Occupational Health. 44. 69-75 (2002)

Ito, T.、Yoshitome, K.、Horike, T. 和 Kira S.：“吸入间二甲苯在大鼠脑中的分布及其对 GABA_A 受体结合的影响”职业健康杂志。

Ito T.,Yoshitome K., Nakayama S.,Kira S. and Horike T.: "Effect of m-xylene on [35S]t-butylbicyclophosphorothionate binding in the rat brain"Soc.Neurosci.Abstr. 26(2). 2080 (2000)

Ito T.、Yoshitome K.、Nakayama S.、Kira S. 和 Horike T.：“间二甲苯对大鼠脑中[35S]叔丁基二环硫代磷酸酯结合的影响”Soc.Neurosci.Abstr。

Ito T., Yoshitome K., Horike T., Kira S.: "Distribution of inhaled m-xylene in rat brain and its effect on GABAA receptor binding"Journal of Occupational Health. 44. 69-75 (2002)

Ito T.、Yoshitome K.、Horike T.、Kira S.：“吸入间二甲苯在大鼠脑中的分布及其对 GABAA 受体结合的影响”职业健康杂志。

Ito T., Yoshitome K., Horike T., Kira S.: "Distribution of inhaled m-xylene in rat brain and its effect on GABAA receptor binding"Journal of Occupational Health. 44(印刷中). (2002)

Ito T.、Yoshitome K.、Horike T.、Kira S.：“吸入间二甲苯在大鼠脑中的分布及其对 GABAA 受体结合的影响”《职业健康杂志》44（出版中）。