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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)
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)
The systemic intraperitoneal (i.p.) administration of the adenosine A2A agonist CGS 21680 was found to dose-dependently antagonize spontaneous and amphetamine-induced (1 mg/kg i.p.) motor activity with similar ED50 values (about 0.2 mg/kg). The ratios between the ED50 values for induction of catalepsy and for antagonizing amphetamine-induced motor activity(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)
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)
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)
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)
Recent pharmacological data suggest that a receptor-receptor interaction between adenosine A2 and dopamine D2 receptors in the brain underlies the behavioral effects of adenosine agonists and adenosine antagonists, such as caffeine and theophylline. According to this interaction, stimulation of A2 receptors inhibits and their blockade potentiates the(More)
Recently evidence has been presented that adenosine A2A and dopamine D2 receptors form functional heteromeric receptor complexes as demonstrated in human neuroblastoma cells and mouse fibroblast Ltk- cells. These A2A/D2 heteromeric receptor complexes undergo coaggregation, cointernalization, and codesensitization on D2 or A2A receptor agonist treatments and(More)
 The ventral striatum is included in brain circuits which connect brain areas classically ascribed to the motor or to the limbic system. In fact, the ventral striatum is involved in the connection between motivationally relevant stimuli and adaptive behaviours. Dopamine neurotransmission in the ventral striatum is essential for the increase in motor(More)