Adenosine A2A and dopamine D2 heteromeric receptor complexes and their function

Kjell Fuxe, Sergi Ferré, Meritxell Canals, Maria Torvinen, Anton Terasmaa, Daniel Marcellino, Steven R. Goldberg, William Staines, Kirsten X. Jacobsen, Carmen Lluis, Amina S. Woods, Luigi F. Agnati, Rafael Franco

Research output: Contribution to journalArticlepeer-review

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 A 2A-D2 heterodimers and/or higher-order A 2A-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 I3 of the D2 receptor are part of the A2A-D2 receptor interface, where electrostatic epitope-epitope interactions involving the N-terminal part of I3 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-D 2 co-trafficking, are the consequence of the existence of an A 2A-D2 receptor heteromer. The relevance of A 2A-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 A 2A-D3 heteromeric receptor complexes in cotransfected cell lines has been summarized.

Original languageEnglish (US)
Pages (from-to)209-219
Number of pages11
JournalJournal of Molecular Neuroscience
Volume26
Issue number2-3
DOIs
StatePublished - Jun 2005
Externally publishedYes

Keywords

  • Adenosine A receptors
  • Dopamine D receptors
  • Heteromers
  • Parkinson's disease
  • Schizophrenia

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry
  • Genetics

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