Pryor G T, Dickinson J, Howd R A, Rebert C S
Neurobehav Toxicol Teratol. 1983 Jan-Feb;5(1):53-7.
In a previous experiment we found that weanling rats subchronically exposed to toluene by inhalation were deficient in learning a multisensory conditioned avoidance response (CAR) task and a tone-intensity discrimination task when trained several hours after each daily 14-hour exposure ended. The present experiment was done to determine whether this deficit represented a residual pharmacologic effect or more persisting nervous system damage. Independent groups of rats were trained on the CAR task either during the last week of a 5-week exposure to 1400 or to 1200 pm toluene (14 hr/day, 7 days/week) or during the first or third weeks after the exposures ended. None of the three groups of toluene-exposed rats were able to acquire the auditory CAR, whereas it had been 4 kHz in the previous experiment. Subsequent tests, in which the frequency and intensity of the tone were varied, revealed that hearing in these rats was unimpaired at 4 kHz, slightly impaired at 8 kHz, and markedly impaired at 12 kHz and above. Thus, although toluene has been shown to be relatively innocuous as a toxicant, this new finding suggests that this solvent should be examined further in terms of its potential hazard, especially with regard to its frequent abuse.
在之前的一项实验中，我们发现，断奶大鼠在每天14小时的吸入甲苯亚慢性暴露结束数小时后接受训练时，在学习多感官条件性回避反应（CAR）任务和音调强度辨别任务方面存在缺陷。进行本实验是为了确定这种缺陷是代表残留的药理作用还是更持久的神经系统损伤。将独立的大鼠组在暴露于1400或1200 ppm甲苯5周的最后一周（每天14小时，每周7天），或者在暴露结束后的第一周或第三周，对CAR任务进行训练。三组暴露于甲苯的大鼠均未能学会听觉CAR，而在前一个实验中该频率为4 kHz。随后进行的测试，其中改变了音调的频率和强度，结果显示这些大鼠在4 kHz时听力未受损，在8 kHz时略有受损，在12 kHz及以上时明显受损。因此，尽管甲苯已被证明作为一种毒物相对无害，但这一新发现表明，这种溶剂的潜在危害应进一步研究，尤其是考虑到其频繁被滥用的情况。
