Article

Adenosine A1 receptor-dopamine D1 receptor interaction in the rat limbic system: modulation of dopamine D1 receptor antagonist binding sites

Department of Neuroscience, Division of Molecular and Cellular Neurochemistry, Karolinska Institute, S171 77 Stockholm, Sweden; Pharmacology Department, Istituto Superiore di Sanitá, Viale Regina Elena, 299, 00161 Rome, Italy
Neuroscience Letters (impact factor: 2.11). 05/1996; DOI:10.1016/0304-3940(96)12577-5 pp.109-112

ABSTRACT Antagonistic interactions between adenosine A2a and dopamine D2 receptors and between adenosine A1 and dopamine D1 receptors have been previously found in the basal ganglia. Those interactions have been proposed to be key mechanisms of action responsible for the motor depressant effects of adenosine agonists and the motor activating effects of adenosine antagonists, like caffeine. By using quantitative receptor autoradiography, the selective adenosine A1 receptor agonist N6-cyclopentyladenosine was found to decrease the affinity of dopamine D1 receptors for the specific D1 antagonist [125I]SCH 23982 in both the nucleus accumbens and the medial prefrontal cortex of the rat brain. The present results suggest that dopamine neurotransmission, through an A1-D1 interaction, might also be involved in the behavioural effects of adenosine agonists and antagonists not related to motor activity, like the sedative-hypnogenic properties of adenosine analogues and the psychostimulant effects of caffeine.

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Keywords

A1-D1 interaction
 
adenosine A1
 
adenosine A2a
 
adenosine agonists
 
adenosine analogues
 
adenosine antagonists
 
Antagonistic interactions
 
basal ganglia
 
behavioural effects
 
dopamine D1 receptors
 
key mechanisms
 
medial prefrontal cortex
 
motor activating effects
 
motor activity
 
motor depressant effects
 
present results
 
psychostimulant effects
 
quantitative receptor autoradiography
 
sedative-hypnogenic properties
 
selective adenosine A1 receptor agonist N6-cyclopentyladenosine