Characterization of triethyl lead chloride neurotoxicity in adult rats

The neurotoxic effects of triethyl lead chloride (TEL) were characterized in adult male Fischer-344 rats. The single dose LD50 (and 95% CI) following SC administration was found to be 11 mg/kg (7.6-13.3 mg/kg), while the LD50 after repeated exposure over five days was found to be 14 mg/kg (8.3-19.0 mg/kg). TEL (1-2.5 mg/kg, SC) given for five days produced a phase of hyperexcitability and hyperactivity 1-2 weeks postdosing, which was followed by hypoexcitability and hypoactivity 3-4 weeks postdosing. TEL also increased hot plate and tail flick latencies during the first two weeks following TEL exposure. Subsequent experiments with an operant titration procedure indicated that TEL increased shock detection thresholds two weeks after cessation of exposure. TEL-exposed rats performed better than controls in a two-way shuttle box avoidance task three weeks after cessation of dosing. Subsequent tests indicated that flinch-jump thresholds of TEL-exposed rats were not affected. The results of these experiments indicate that TEL produces a profile of toxicity characterized by changes in reactivity or emotionality possibly similar to that of animals having lesions in limbic forebrain areas.