Changes in auditory brainstem response in rats chronically exposed to carbon disulfide.

The chronic effect of carbon disulfide (CS2) on the central nervous system (CNS) was studied by examining auditory brainstem responses (ABRs) in female rats (Jcl Wistar) exposed to 200 ppm or 800 ppm CS2 by inhalation, 6 h a day, 5 days a week, for 15 weeks. Two modes of ABRs evoked by clicks at 61 and 96 dB sound pressure levels (61 dB-ABR and 96 dB-ABR) were recorded during the exposure and for 6 weeks afterwards. Three main components (I, III and V) of ABRs were analyzed from the latencies and differences between latencies of them (interpeak latencies, IPL I-III, IPL III-V and IPL I-V). The latencies of the three components and IPLs of 96 dB-ABR in rats group exposed to 800 ppm of CS2 were significantly delayed during the exposure period. The delay of latency of component V and IPL III-V and I-V tended to increase with exposure time. At 61 dB-ABR, the changes in the latency of component V, IPL III-V and I-V resembled those at 96 dB-ABR. For the rats group exposed to 200 ppm CS2, the latency of component I, IPL III-V and I-V at 96 dB-ABR were delayed significantly but transiently during the exposure period. For both groups, recovery from the latencies of the three components and IPLs of ABR was observed by the end of the recovery period. The delayed latencies of ABR observed in rats exposed to 800 ppm CS2 suggested a conduction dysfunction in the brainstem due to CS2 exposure.(ABSTRACT TRUNCATED AT 250 WORDS)