Atrophy of the striatum and motor disturbance induced by colchicine

To determine the functional role of the striatonigral system in the circling behavior of rats and the mode of action of colchicine, we investigated the circling behavior induced by dopamine agonists after microinjection of colchicine into the unilateral striatum. Both apomorphine and methamphetamine produced ipsilateral circling behaviors in rats injected with colchicine, indicating that ipsilateral striatonigral pathways were damaged by the drug. Histological and biochemical examinations showed that intracaudate injection of colchicine damaged not only the dopaminergic neurons but also caused atrophy of the striatum with loss of neuronal perikarya. These results suggest that treatment with colchicine may be used as a model of senile atrophy or degenerative atrophy in these animals.