Immunological identification of A1 adenosine receptors in brain cortex

J Neurosci Res. 1995 Dec 15;42(6):818-28. doi: 10.1002/jnr.490420610.


The A1 adenosine receptor from pig brain cortex has been identified by means of two antipeptide antibodies against two domains of the receptor molecule: PC/10 antiserum was raised against a part of the third intracellular loop, and PC/20 antiserum was raised against a part of the second extracellular loop. PC/10 antibody was able to recognize a 39-kDa band that corresponded to the A1 receptor, as demonstrated by immunoblotting and by immunoprecipitation of the molecule cross-linked to [125I](R)-2-azido-N2-p-hydroxy(phenylisopropyl)adenosine. Besides the 39-kDa band, PC/20 also recognized a 74-kDa form that does not seem to correspond to a receptor-G protein complex. The occurrence of the two bands was detected and analyzed in samples from different species and tissues showing a heterogeneous distribution of both. The 74-kDa form can be converted into the 39-kDa form by treatment with agonists or antagonists of A1 adenosine receptors. These results suggest that A1 adenosine receptor can occur in dimers and that the dimer-monomer conversion might be regulated by adenosine as the physiological ligand. Since the 74-kDa aggregates were not recognized by PC/10, it is likely that part of the third intracellular loop participates in the protein-protein interaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cerebral Cortex / metabolism*
  • Immunoblotting
  • Immunohistochemistry
  • Male
  • Radioligand Assay
  • Rats
  • Receptors, Purinergic P1 / metabolism*
  • Swine


  • Receptors, Purinergic P1