Evidence for an involvement of striatal D1 receptors in levodopa-induced @entity910 has been presented whereas the contribution of striatal D2 receptors remains controversial. In addition, whether D1 and D2 receptors located in the substantia nigra reticulata shape the response to levodopa remains unknown. We therefore used dual probe microdialysis to unravel the impact of striatal and nigral D1 or D2 receptor blockade on abnormal @entity2358 (AIMs) and striatal output pathways in unilaterally @entity2955 lesioned dyskinetic @entity35 . Regional perfusion of @entity69453 ( @entity10095 ) and D2/D3 ( @entity11641 ) receptor antagonists was combined with systemic administration of levodopa. Levodopa-induced AIMs coincided with a prolonged surge of @entity1246 and @entity2227 levels in the substantia nigra reticulata. Intrastriatal @entity10095 attenuated the @entity3034 -induced AIM scores (~50%) and prevented the accompanying neurochemical response whereas @entity11641 was ineffective. When perfused in the substantia nigra, both antagonists attenuated AIM expression (~21-40%). However, only intranigral @entity10095 attenuated levodopa-induced nigral @entity1246 efflux, whereas @entity11641 reduced basal @entity1246 levels without affecting the response to levodopa. In addition, intranigral @entity11641 elevated @entity535 release in the striatum and revealed a (mild) facilitatory effect of levodopa on striatal @entity2227 . We conclude that both striatal and nigral D1 receptors play an important role in @entity910 possibly via modulation of the striato-nigral direct pathway. In addition, the stimulation of nigral D2 receptors contributes to @entity910 while modulating @entity2227 and @entity1246 efflux both locally and in the striatum.

In vivo evidence for a differential contribution of striatal and nigral D1 and D2 receptors to @entity3034 induced @entity910 and the accompanying surge of nigral XXXX levels.

@entity10095 :: ('MESH:C534628', 'Chemical') :: ['SCH23390'] @entity2227 :: ('CHEBI:29987', 'Chemical') :: ['glutamate'] @entity3034 :: ('MESH:D007980', 'Chemical') :: ['levodopa'] @entity1246 :: ('MESH:D005680', 'Chemical') :: ['GABA'] @entity535 :: ('CHEBI:33704', 'Chemical') :: ['amino acid'] @entity2358 :: ('MESH:D020820', 'Disease') :: ['involuntary movements'] @entity910 :: ('MESH:D004409', 'Disease') :: ['dyskinesia'] @entity35 :: ('10116', 'Species') :: ['rats'] @entity2955 :: ('MESH:D016627', 'Chemical') :: ['6-hydroxydopamine'] @entity69453 :: ('117060(Tax:10116)', 'Gene') :: ['D1/D5'] @entity11641 :: ('MESH:D020891', 'Chemical') :: ['raclopride']
@entity535 :: (CHEBI:33704,Chemical) :: ['amino acid']
