Pryor G T, Howd R A
Neurobehav Toxicol Teratol. 1986 Jan-Feb;8(1):103-4.
Inhalation exposure of rats to toluene causes irreversible hearing loss (e.g., Pryor et al.). To determine whether noise emanating from the inhalation system was a major contributing factor and whether exposure by a noninhalation route would cause a similar effect, weanling, male Fischer-344 rats were injected SC twice daily in a quiet environment with PEG-300 (control) or with 1.5 or 1.7 g/kg of toluene for 7 days. After being trained to perform a multisensory conditioned avoidance response (CAR) task, tone intensity-response functions were generated at 4, 8, 12, and 20 kHz, and behavioral auditory response thresholds were estimated. Toluene caused a dose-related hearing loss at frequencies of 8 kHz and above, with no effect on performance of the CAR in response to light, nonaversive footshock, or the 4-kHz tone. The similarity of this effect to that observed following inhalation exposure indicates that noise is not a major factor in the toluene-induced hearing loss, although possible interactions between noise and toluene remain to be investigated. These results also demonstrate that direct penetration of the toluene vapors through the external ear structure, as might occur during inhalation exposure, is not a necessary condition for inducing the hearing loss.
让大鼠吸入甲苯会导致不可逆的听力损失（例如，Pryor等人的研究）。为了确定吸入系统发出的噪音是否是主要促成因素，以及非吸入途径的暴露是否会产生类似的影响，在安静环境中，对断奶的雄性Fischer-344大鼠每天皮下注射两次聚乙二醇300（对照）或1.5或1.7 g/kg甲苯，持续7天。在训练大鼠执行多感官条件性回避反应（CAR）任务后，分别在4、8、12和20 kHz频率下生成音调强度-反应函数，并估计行为听觉反应阈值。甲苯在8 kHz及以上频率导致剂量相关的听力损失，对大鼠对光、无厌恶感的足部电击或4 kHz音调的CAR表现没有影响。这种效应与吸入暴露后观察到的效应相似，表明噪音不是甲苯诱导听力损失的主要因素，尽管噪音和甲苯之间可能的相互作用仍有待研究。这些结果还表明，吸入暴露期间甲苯蒸气可能通过外耳结构直接渗透，并非诱发听力损失的必要条件。
