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Increasing evidence suggests that antagonistic interactions between specific subtypes of adenosine and dopamine receptors in the basal ganglia are involved in the motor depressant effects of adenosine receptor agonists and the motor stimulant effects of adenosine receptor antagonists, such as caffeine. The GABAergic striatopallidal neurons are regulated by(More)
Antagonistic and reciprocal interactions are known to exist between adenosine and dopamine receptors in the striatum. In the present study, double immunofluorescence experiments with confocal laser microscopy showed a high degree of colocalization of adenosine A(2A) receptors (A(2A)R) and dopamine D(2) receptors (D(2)R) in cell membranes of SH-SY5Y human(More)
The functional role of heteromers of G-protein-coupled receptors is a matter of debate. In the present study, we demonstrate that heteromerization of adenosine A1 receptors (A1Rs) and A2A receptors (A2ARs) allows adenosine to exert a fine-tuning modulation of glutamatergic neurotransmission. By means of coimmunoprecipitation, bioluminescence and(More)
Adenosine A2A receptors are highly enriched in the basal ganglia system. They are predominantly expressed in enkephalin-expressing GABAergic striatopallidal neurons and therefore are highly relevant to the function of the indirect efferent pathway of the basal ganglia system. In these GABAergic enkephalinergic neurons, the A2A receptor tightly interacts(More)
There has been a long debate about the predominant involvement of the different adenosine receptor subtypes and the preferential role of pre- versus post-synaptic mechanisms in the psychostimulant effects of the adenosine receptor antagonist caffeine. Both striatal A(1) and A(2A) receptors are involved in the motor-activating and probably reinforcing(More)
Since high-affinity adenosine A2 receptors (A2a) are localized exclusively in dopamine-rich regions in the central nervous system and mediate inhibition of locomotor activity, we have examined the effect of A2a receptor activation on D1 and D2 receptor binding in membrane preparations of the rat striatum. The A2a agonist(More)
There is evidence for strong functional antagonistic interactions between adenosine A2A receptors (A2ARs) and dopamine D2 receptors (D2Rs). Although a close physical interaction between both receptors has recently been shown using co-immunoprecipitation and co-localization assays, the existence of a A2AR-D2R protein-protein interaction still had to be(More)
The physiological meaning of the coexpression of adenosine A2A receptors and group I metabotropic glutamate receptors in gamma- aminobutyric acid (GABA)ergic striatal neurons is intriguing. Here we provide in vitro and in vivo evidence for a synergism between adenosine and glutamate based on subtype 5 metabotropic glutamate (mGluR5) and adenosine A2A (A2AR)(More)
The function of dopamine D(3) receptors present in the striatum has remained elusive. In the present study evidence is provided for the existence of dopamine D(1)-D(3) receptor heteromers and for an intramembrane D(1)-D(3) receptor cross-talk in living cells and in the striatum. The formation of D(1)-D(3) receptor heteromers was demonstrated by fluorescence(More)
The possible molecular basis for the previously described antagonistic interactions between adenosine A(1) receptors (A(1)R) and dopamine D(1) receptors (D(1)R) in the brain have been studied in mouse fibroblast Ltk(-) cells cotransfected with human A(1)R and D(1)R cDNAs or with human A(1)R and dopamine D(2) receptor (long-form) (D(2)R) cDNAs and in(More)