By subchronic exposure to low level of organic solvents, does aging potentiate the effects on the receptors in the CNS?

【目的和方法】从成熟到老年的过渡伴随着许多退化过程，其中一些可以被假设为增强动物对环境化学物质（如有机溶剂）不利影响的脆弱性。为了研究反复暴露于低水平甲苯的大鼠中枢神经系统（CNS）慢性效应的易感性，采用[^3H]QNB和Brandel公司（M-30）的收割机放射标记受体结合法测定了大脑皮层和海马中胆碱能毒碱受体（mAch-R）的Bmax和Kd，并采用Prism（GraphPad公司）分析了青年和老年Fischer雄性大鼠，每组6只大鼠。在12周重复甲苯最终暴露后第3天和第14天。在4个月大的年轻成年大鼠和21个月大的老年大鼠中，每天3小时，每周5天，连续12周暴露于0、50、100和1000ppm的甲苯水平。【结果】在本实验条件下，通过统计分析和SPSS的方差分析，无法检测到衰老和亚慢性低水平甲苯暴露对CNS mAch-R的Bmax和Kd的联合影响。

[Objective and Methods] The transition from matuarity to advanced age is accompanied by a multitude of degenerative processes, several of which could be hypothesized to enhance the vulnerability of animals to the adverse effects of environmental chemicals such as organic solvents.To examine susceptibility to chronic effects in the central nervous system(CNS) in rats which were repeatedly exposed to low level of toluene, Bmax and Kd of the cholinergic muscarinic receptor(mAch-R) in the cerebral cortex and hippocampus were determined by radiolabeled receptor binding assay using [^3H]QNB and harvester of Brandel co.(M-30), and analyzed by Prism(GraphPad co.) in young adult and elderly Fischer strain male rats, 6rats in each group, at the 3rd day and 14th day following final exposure of 12weeks-repeated-exposures of toluene. Exposure started at the 4months of age in young adult rats, and 21months of age in elderly rats with the regimen of 3hours in a day, 5days a week for 12weeks at the levels of 0, 50, 100 and 1,000ppm of toluene. [Results] Combined effects of aging and subchronic exposure to low level of toluene on the Bmax and Kd of the mAch-R in the CNS could not be detected in the conditions of this experiment by statistical analysis, ANOVA of SPSS.