Review

Journal of Molecular Neuroscience

, Volume 26, Issue 2, pp 209-220

First online:

Adenosine A2A and dopamine D2 heteromeric receptor complexes and their function

  • Kjell FuxeAffiliated withDepartment of Neuroscience, Division of Cellular and Molecular Neurochemistry, Karolinska Institutet Email author 
  • , Sergi FerréAffiliated withNational Institute on Drug Abuse, DHHS, NIH, Intramural Research Program
  • , Meritxell CanalsAffiliated withDepartment of Neuroscience, Division of Cellular and Molecular Neurochemistry, Karolinska Institutet
  • , Maria TorvinenAffiliated withDepartment of Neuroscience, Division of Cellular and Molecular Neurochemistry, Karolinska Institutet
  • , Anton TerasmaaAffiliated withDepartment of Neuroscience, Division of Cellular and Molecular Neurochemistry, Karolinska Institutet
  • , Daniel MarcellinoAffiliated withDepartment of Biochemistry and Molecular Biology, University of Barcelona
  • , Steven R. GoldbergAffiliated withNational Institute on Drug Abuse, DHHS, NIH, Intramural Research Program
  • , William StainesAffiliated withCellular and Molecular Medicine, University of Ottawa
  • , Kirsten X. JacobsenAffiliated withCellular and Molecular Medicine, University of Ottawa
    • , Carmen LluisAffiliated withDepartment of Biochemistry and Molecular Biology, University of Barcelona
    • , Amina s. WoodsAffiliated withNational Institute on Drug Abuse, DHHS, NIH, Intramural Research Program
    • , Luigi F. AgnatiAffiliated withDepartment of Biomedical Sciences, University of Modena and Reggio Emilia
    • , Rafael FrancoAffiliated withDepartment of Biochemistry and Molecular Biology, University of Barcelona

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Abstract

The existence of A2A-D2 heteromeric complexes is based on coimmunoprecipitation studies and on fluorescence resonance energy transfer and bioluminescence resonance energy transfer analyses. It has now become possible to show that A2A and D2 receptors also coimmunoprecipitate in striatal tissue, giving evidence for the existence of A2A-D2 heteromeric receptor complexes also in rat striatal tissue. The analysis gives evidence that these heteromers are constitutive, as they are observed in the absence of A2A and D2 agonists. The A2A-D2 heteromers could either be A2A-D2 heterodimers and/or higher-order A2A-D2 hetero-oligomers. In striatal neurons there are probably A2A-D2 heteromeric complexes, together with A2A-D2 homomeric complexes in the neuronal surface membrane. Their stoichiometry in various microdomains will have a major role in determining A2A and D2 signaling in the striatopallidal GABA neurons. Through the use of D2/D1 chimeras, evidence has been obtained that the fifth transmembrane (TM) domain and/or the 13 of the D2 receptor are part of the A2A-D2 receptor interface, where electrostatic epitope-epitope interactions involving the N-terminal part of 13 of the D2 receptor (arginine-rich epitope) play a major role, interacting with the carboxyl terminus of the A2A receptor. Computerized modeling of A2A-D2 heteromers are in line with these findings. It seems likely that A2A receptor-induced reduction of D2 receptor recognition, G protein coupling, and signaling, as well as the existence of A2A-D2 co-trafficking, are the consequence of the existence of an A2A-D2 receptor heteromer. The relevance of A2A-D2 heteromeric receptor complexes for Parkinson’s disease and schizophrenia is emphasized as well as for the treatment of these diseases. Finally, recent evidence for the existence of antagonistic A2A-D3 heteromeric receptor complexes in cotransfected cell lines has been summarized.

Index Entries

Adenosine A2A receptors dopamine D2 receptors heteromers Parkinson’s disease schizophrenia