Behavioural effects of tetrachloroethylene exposure in rats: acute and subchronic studies

This study was carried out to compare the neurobehavioural profile of acute and subchronic tetrachloroethylene (perchloroethylene, PCE) exposure in rats. In the acute study, a single bolus of 50 and 500 mg/kg of PCE in corn oil was administered by gavage. In the subchronic experiments, rats were exposed to PCE at a dosage of 5 and 50 mg/kg in corn oil, 5 days per week for 8 weeks. Nociception, locomotion and seizure susceptibility was tested using open-field, tail immersion and hot plate and pentylenetetrazol-induced seizures, respectively. Subchronic PCE exposure exhibited higher antinociceptive effect and lower motor activity in comparison with acute exposure. Pentylenetetrazol-induced convulsion thresholds were elevated following acute PCE exposure. In contrast, subchronic PCE exposure only increased thresholds for myoclonic twitch and face and forelimb clonus without altering the thresholds for running and bouncing clonus and tonic hindlimb extension. These findings suggest that subchronic PCE exposure results in progressively greater toxic effects on nociception and locomotor activity. The differential effects on seizure susceptibility between acute and subchronic exposure may represent different alterations on neural circuits involved in seizure generation.