D1-D2 DOPAMINE-RECEPTOR INTERACTION - AN IN-VIVO SINGLE-UNIT ELECTROPHYSIOLOGICAL STUDY

AFTER intrastriatal administration of selective dopamine receptor agon ists only a small percentage of substantia nigra pars reticulata singl e units showed changes in firing rate (23% after SKF38393 and 17% afte r quinpirole). After their intrastriatal co-administration, however, o r after the application of the non-selective dopamine receptor agonist apomorphine, 72% and 69% of units responded, respectively. This resul t confirms the participation of the striatum in the phenomenon of D1-D 2 receptor interaction, and show that co-activation of both receptor s ubtypes produced a maximal effect on basal ganglia output nuclei.