Arito H, Takahashi M, Tsuruta H, Ishikawa T
National Institute of Industrial Health, Kawasaki Japan.
Ind Health. 1994;32(3):129-44. doi: 10.2486/indhealth.32.129.
Age-related effects of trichloroethylene (TRI) inhalation on heart rate (HR), its circadian rhythm, the incidence of spontaneous bradyarrhythmias (BA) and ventricular premature contractions (VPC) were examined in conscious rats, as was the dependence of arrhythmias on sleep-wakefulness. Indwelling electrodes were used for simultaneous electrocardiographic (ECG), electroencephalographic (EEG) and electromyographic (EMG) measurements in 2, 13, 20 and 26-month old rats. The rats were exposed for 8 hours to 300 ppm TRI followed by exposure to clean air for 7 days, after which they were exposed to 1,000 ppm for 8 hours. The polygraphic recordings were made during 8-hr exposures and for 28 hours thereafter. Control values for all physiological parameters were measured during 36-hr exposure to clean air. The exposure to TRI exacerbated an age-dependent decrease in HR and its circadian amplitude. Although the spontaneous BA incidence decreased with advancing age, the ratio of the number of BA episodes during the post-exposure period after TRI exposure to those during the corresponding period of clean-air exposure increased more pronouncedly for 20 and 26-month old rats than for 2 and 13-month old rats. The number of spontaneous VPC episodes increased for 20 and 26-month old rats but was not affected by the exposure to TRI. Gas chromatographic analysis of TRI and free trichloroethanol (TRI-OH) in the brain and blood of the TRI-exposed rats revealed the prolonged half-life of TRI and the delayed clearance of free TRI-OH from the tissues with advancing age. The age-related exacerbation of those ECG responses to TRI inhalation appears to be brought about in part by the age-related change in the pharmacokinetics of TRI and TRI-OH.
在清醒大鼠中研究了三氯乙烯（TRI）吸入对心率（HR）、其昼夜节律、自发性缓慢性心律失常（BA）和室性早搏（VPC）发生率的年龄相关影响，以及心律失常对睡眠-觉醒的依赖性。对2、13、20和26月龄大鼠使用植入式电极同步进行心电图（ECG）、脑电图（EEG）和肌电图（EMG）测量。大鼠先暴露于300 ppm的TRI中8小时，然后暴露于清洁空气中7天，之后再暴露于1000 ppm的TRI中8小时。在8小时暴露期间及之后的28小时内进行多导记录。在暴露于清洁空气36小时期间测量所有生理参数的对照值。TRI暴露加剧了HR随年龄增长的下降及其昼夜振幅的下降。尽管自发性BA的发生率随年龄增长而降低，但20和26月龄大鼠在TRI暴露后暴露期的BA发作次数与相应清洁空气暴露期的发作次数之比，比2和13月龄大鼠增加得更明显。20和26月龄大鼠的自发性VPC发作次数增加，但不受TRI暴露的影响。对TRI暴露大鼠的大脑和血液中的TRI和游离三氯乙醇（TRI-OH）进行气相色谱分析发现，随着年龄的增长，TRI的半衰期延长，游离TRI-OH从组织中的清除延迟。吸入TRI后这些ECG反应的年龄相关加剧似乎部分是由TRI和TRI-OH药代动力学的年龄相关变化引起的。
