COMBINED EFFECTS OF SIMULTANEOUS EXPOSURE TO TOLUENE AND ETHANOL ON AUDITORY FUNCTION IN RATS

Three experimental groups and one control group of Long-Evans rats wer e used to study the combined effects of toluene and ethanol on auditor y function. The first experimental group was exposed to toluene vapors (1750 ppm, 6 h/day, 5 days/week, 4 weeks), the, second one was daily gavaged with a saline solution of ethanol (4 g/kg, 4 weeks), and the l ast group was simultaneously exposed to both toluene and ethanol. Audi tory function was tested by recording brain stem (inferior colliculus) auditory-evoked potentials for audiometric frequencies ranging from 2 to 32 kHz. Urinary hippuric acid was dosed to check the toluene metab olism during the experiments. Ethanol clearly modified the toluene met abolism in the present experimental conditions. As a result, the heari ng loss induced by a simultaneous exposure to both ethanol and toluene was larger than that induced by exposure to toluene alone. (C) 1998 E lsevier Science Inc.