Kainic acid injections in the striatum alter the cataleptic and locomotor effects of drugs influencing dopaminergic and cholinergic systems.

Rats with bilateral injections of kainic acid into the striatum were tested for their motor responsiveness to drugs influencing dopaminergic and cholinergic systems. The kainic acid-induced lesions potentiated the locomotor response to both the dopaminergic agonist, d-amphetamine, and the cholinergic antagonist, scopolamine, attenuated the cataleptic response to the dopaminergic antagonist, haloperidol, and potentiated the cataleptic acid and convulsive responses to the cholinergic agonist, pilocarpine. The analogy of these pharmacological effects with those induced by similar drugs in patients with Huntington's disease supports the view that this animal preparation is a useful model of Huntington's disease. The opposite effects of haloperidol and pilocarpine on catalepsy in kainic acid-lesioned rats suggest that more work should be done to elucidate the mechanism behind this conflict before full support can be given to its use as a model system for evaluating possible pharmacotherapy in Huntington's disease.