Correlation between rotational behaviors and neurochemical changes associated with damage of rat striatum: Analysis using unilateral microinjection of kainic acid

Abstract

The correlation between rotational behaviors and neurochemical changes associated with the striatal damage induced by an unilateral microinjection of kainic acid were investigated. Shortly after the unilateral striatal injection of kainic acid, rats exhibited contralateral rotational behaviors, and these changes were antagonized by the simultaneous striatal injection of haloperidol. On the other hand, systemic injection of methamphetamine to animals having the lesion on nigro-striatal dopaminergic neurons exhibited ipsilateral turnings. In addition, it was found that the release of [ 14C]dopamine from striatal slices was increased by the in vitro addition of kainic acid. Following 2 days after the striatal injection of kainic acid and thereafter, the rats exhibited ipsilateral rotational behaviors and microinjection of muscimol into the ipsilateral substantia nigra of these animals altered turning movements to a contralateral type. Simultaneous nigral injection of bicuculline antagonized to the muscimol-induced contralateral turnings. These results suggest that the increase of dopamine release from dopaminergic neurons in the striatum may be involved in the occurrence of contralateral turning behaviors observed shortly after the striatal kainic acid treatment. The present results also suggest that changes in the functional states of striatonigral GABA-ergic neurons may play an important role in the occurrence of ipsilateral rotational movements at a late stage following the striatal injection of this agent.