Investigation on autonomic neurotoxicity of hazardous factors in environmental and occupational health

为阐明铅、甲苯、正己烷、二甲苯和甲苯等有机溶剂、苯乙烯、酒精、振动工具操作和视频显示终端(VDT)作业等有害因素对环境和职业健康的自主神经毒性作用，对接触这些因素的受试者进行了心电图R-R间期变异性(CV&lt；RR&gt；)的测定。除VDT工作外，暴露于所有因素均可导致副交感神经功能减退；此外，铅和酒精似乎影响交感神经活动。在对环境和职业因素对自主神经系统影响的研究综述的基础上，得到以下发现：(1)排除上述因素，研究了三氯乙烯、二硫化碳和混合农药对自主神经功能的影响。严重的CV…抑制接触二硫化碳和混合农药的工人有更多的副交感神经活动，而长期接触三氯乙烯的工人与健康对照组的任何CV；；RR&>；参数均无显著差异。(2)大多数因素似乎主要通过抑制副交感神经活动来影响CV；另一方面，据报道，心脏迷走神经张力降低与心源性猝死或冠状动脉疾病的风险增加有关；此外，心率变异性的测量及其频谱成分的量化是心血管发病率和死亡率的有力预测因子。因此，应特别注意进一步发现危险因素，可能导致环境和职业健康中的一些副交感神经功能障碍。(3)根据这些数据和以前关于中枢和外周神经毒性的数据，自主神经系统中铅的细胞靶点可能是交感神经和迷走神经，有机溶剂和振动工具操作的细胞靶点可能在脑干内。较少

To clarify the autonomic neurotoxicites of several hazardous factors in environmental and occupational health, such as lead, toluene, organic solvents including n-hexane, xylene and toluene, stirene, alcohol, vibrating tool operation and video display terminal (VDT) work, the electrocardiographic R-R interval variability (CV_<RR>) was measured in subjects exposed to such factors. Exposures to all the factors, except VDT work, are suggested to cause parasympathetic hypofunction ; in addition, lead and alcohol seem to affect the sympathetic activity. However, no significant effect of VDT work on the autonomic nervous system was found.Based upon an overview of research addressing the effects of environmental and occupational factors on the autonomic nervous system, the following finding were obtained :(1) Excluding the above factors, the effects of trichloroethene, carbon disulphide and mixed pesticides on autonomic nervous function have been investigated. Significant depression of the CV … More _<RR> has been shown in workers exposed to carbon disulphide and mixed pesticides, whereas there were no significant differences in any CV_<RR> parameters between workers with long-term exposure to trichloroethene and healthy controls.(2) Most of the factors appear to have affected the CV_<RR> mainly through depression of parasympathetic activity, suggesting that parasympathetic function is more susceptible to such factors in the environment and workplace than sympathetic function. On the other hand, decreased cardiac vagal tone has been reported to be associated with an increased risk of sudden cardiac death or coronary artery disease ; also, measurements of heart rate variability and the quantification of its spectral components are powerful predictors of cardiovascular morbidity and mortality. Therefore, particular attention should be directed to further discovery of hazardous factors, possibly causing some parasympathetic dysfunction in environmental and occupational health.(3) In the light of these data and previous data regarding the central and peripheral neurotoxicities, the cellular targets of lead in the autonomic nervous system are supposed to be the sympathetic and vagal nerves, and those of organic solvents and vibrating tool operation may be within the brainstem. Less