On chorea: possible neuronal mechanisms.

The mechanism of generation of choreic movements is a rather difficult issue to be elucidated, chiefly due to the lack of a good animal model. Recently we have succeeded to reproduce choreic movements in monkey by using kainic acid lesion of the striatum and the administration of L-dopa. Based on the morphological and biochemical findings of monkey brains, we proposed the hypothesis for the mechanism of choreic movements to be the presynaptic "activation" of the nigro-striatal dopaminergic pathways rather than the postsynaptic dopaminergic receptors in the striatum. This hypothesis coincide well with the clinical and clinico-pharmacological experience in Huntington's disease. The possible mechanisms of the dopaminergic "activation" are discussed.