Detection of antigen interactions ex vivo by proximity ligation assay: endogenous dopamine D2-adenosine A2A receptor complexes in the striatum

Biotechniques. 2011 Aug;51(2):111-8. doi: 10.2144/000113719.


The existence of G protein-coupled receptor (GPCR) dimers and/or oligomers has been demonstrated in heterologous systems using a variety of biochemical and biophysical assays. While these interactions are the subject of intense research because of their potential role in modulating signaling and altering pharmacology, evidence for the existence of receptor interactions in vivo is still elusive because of a lack of appropriate methods to detect them. Here, we adapted and optimized a proximity ligation assay (PLA) for the detection in brain slices of molecular proximity of two antigens located on either the same or two different GPCRs. Using this approach, we were able to confirm the existence of dopamine D2 and adenosine A2A receptor complexes in the striatum of mice ex vivo.

MeSH terms

  • Analysis of Variance
  • Animals
  • Antibodies / chemistry
  • Antibodies / metabolism
  • Corpus Striatum / chemistry*
  • Corpus Striatum / metabolism
  • Immunoblotting / methods*
  • Immunohistochemistry / methods*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Microscopy, Confocal
  • Receptor, Adenosine A2A / analysis*
  • Receptor, Adenosine A2A / chemistry
  • Receptor, Adenosine A2A / metabolism
  • Receptors, Dopamine D2 / analysis*
  • Receptors, Dopamine D2 / chemistry
  • Receptors, Dopamine D2 / metabolism


  • Antibodies
  • Receptor, Adenosine A2A
  • Receptors, Dopamine D2