[Neurotoxicity of allyl chloride in rats. Dose-effect relationship following long-term exposure]

To elucidate the dose-effect relationship of neurotoxicity of allyl chloride (AC) in Donryu rats, 5 animals each were exposed to 10, 50 and 100 ppm AC for 8 h/d and 5 d/wk for a period of 34 wk. Nerve conduction velocities of the tail nerve in rats were determined before and after 4, 8, 12, 16, 22, 28 and 34 wk of exposure, and the width of landing foot-spread after 8, 12, 16, 28 and 34 wk. Animals subjected to 100 ppm AC showed significant (p less than 0.01) reduction of motor and sensory nerve conduction velocities and nerve action potentials (NAP) after 28 wk when clinical signs of neuropathy were observed, i.e., weakness of hindlimbs and significantly (p less than 0.01) extended landing foot-spreads. Motor distal latency was retarded in rats exposed to 100 ppm AC at the last period of exposure. In rats exposed to 50 and 100 ppm AC, no remarkable electrophysiological findings or abnormal clinical signs were observed except for depressed amplitude of NAP in 50 ppm-exposed rats when compared with those exposed to 10 ppm.