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

[目的与方法]研究低浓度甲苯对大鼠中枢神经系统（CNS）慢性损伤的敏感性，探讨甲苯对大鼠中枢神经系统慢性损伤的影响。用[^3H]QNB和Brandel公司的harvester法测定大脑皮层和海马胆碱能M受体（mAch-R）的Bmax和Kd。（M-30），并通过Prism（GraphPad co.）青年和老年Fischer系雄性大鼠，每组6只，在甲苯12周重复暴露后第3天和第14天，在0、50、100和1，000 ppm甲苯水平下，年轻成年大鼠在4月龄时开始暴露，老年大鼠在21月龄时开始暴露，方案为每天3小时，每周5天，持续12周。[结果]在本实验条件下，经SPSS统计分析、方差分析，未检测到年龄和亚慢性低浓度甲苯暴露对中枢神经系统mAch-R的Bmax和Kd的联合作用。

[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.