Long-term behavioural effects of TaClo (1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline) after subchronic treatment in rats.

1-Trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo), which shows a great structural similarity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), when administered to rats lead to enhanced spontaneous locomotion when they were tested 4-9 days after subchronic injection at a daily dose of 0.2 mg/kg over a seven week period. However, 9 weeks after the end of the course of injections animals walked more slowly during 12 hours of nocturnal activity, and apomorphine-induced locomotion was decreased 12 weeks later. These results suggest that the drug may exert a progressive neurotoxic effect.