Kainic acid lesions of the striatum: behavioural sequalae similar to Huntington's chorea.

Kainic acid (3 nmoles bilaterally) was injected into the dorsal striatum of the rat producing virtually complete destruction of cell bodies in this structure but without directly affecting the dopamine terminals ascending from the substantia nigra and terminating in the striatum. Other fibres of passage, such as the internal capsule, were also spared. The locomotor and stereotypy responses to doses of amphetamine, a dopamine releasing agent, were found to be consistently enhanced after this lesion. The stereotypy and locomotor activity in response to the direct receptor agonist, apomorphine, however were not consistently affected. The results are interpreted in terms of a functional dichotomy between dorsal and ventral striatum and in terms of previously demonstrated electrophysiological alterations in the striatonigral feedback loop after kainic acid injection. Similarities are noted with the effects of these two stimulant drugs in human patients with Huntington's disease, thus strengthening the kainic acid animal model of this disease, first proposed on biochemical grounds.