TRANSIENT COGNITIVE DEFICITS AND HIGH-FREQUENCY HEARING-LOSS IN WEANLING RATS EXPOSED TO TOLUENE

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  • 1 January 1983
    • journal article
    • research article
    • Vol. 5  (1) , 53-57
Abstract
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 h after each daily 14 h exposure ended. Whether this deficit represented a residual pharmacologic effect or more persisting nervous system damage was assessed. Independent groups of rats were trained on the CAR task during the last week of a 5 wk exposure to 1400 or 1200 ppm toluene (14 h/day, 5 days/wk) or during the 1st or 3rd wk after exposures ended. No group of toluene-exposed rats acquired the auditory CAR; they learned the visual and somesthetic CAR. The frequency of the tone was 20 kHz in this experiment; 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 .gtoreq. 12 kHz. Although toluene was relatively innocuous as a toxicant, this solvent should be examined further in terms of its potential hazard, especially with regard to its frequent abuse.