GABAergic mechanisms mediating rotational behavior in rats: differences between dorsal and ventral striatum.

Local injection of muscimol into the dorsal or ventral striatum of rats did not induce any rotational activity, but injection of picrotoxin into ventral striatal aspects induced an intense contralateral rotation. Amphetamine pretreatment resulted in an ipsilateral rotation after muscimol injection into dorsal striatum and in a complex rotational pattern after ventral injection, characterized by an initial short-lasting ipsilateral rotation followed by a long-lasting contralateral rotation. The contralateral rotation induced by picrotoxin was abolished by amphetamine pretreatment. These results indicate a functional heterogeneity between dorsal and ventral striatal mechanisms mediating rotational behavior, and a different pattern of dopamine-GABA interactions between dorsal and ventral striatum.