Behavioural topography in the striatum: differential effects of quinpiroleand D-amphetamine microinjections

Behavioural evidence has accumulated that supports the hypothesis that spec ific territories of the striatum contribute differentially to the control o f motor behaviours. The present experiments compare the behavioural effects of microinjections of amphetamine (20 mu g/0.5 mu 1) with those elicited b y the D-2-class dopamine receptor agonist quinpirole (3 mu g/0.5 mu l) foll owing direct microinjection into three anatomically distinct sectors of the striatum: the nucleus accumbens; the ventrolateral striatum and the antero dorsal striatum. Our findings demonstrate that site-specific behavioural re sponses are induced by microinjections of amphetamine, but not of quinpirol e, into the striatum. Our results suggest that widespread areas of the stri atum are implicated in the induction of a syndrome of sedation, yawning and motor inhibition, observed readily following microinjections of quinpirole into the striatum. This evidence supports both homogeneity and segregation of function in the striatum at the behavioural level. Further, the results suggest that the elicitation of site-specific action sequences at the leve l of the striatum seems to require cooperative interactions between D-1-cla ss and D-2-class dopamine receptors. (C) 1998 Elsevier Science B.V. All rig hts reserved.