Molecular cloning of the rat A2 adenosine receptor: selective co-expression with D2 dopamine receptors in rat striatum

Brain Res Mol Brain Res. 1992 Jul;14(3):186-95. doi: 10.1016/0169-328x(92)90173-9.


A cDNA fragment homologous to other G protein-coupled receptors was isolated from rat brain using the PCR method and demonstrated to be abundantly expressed in striatum. Using this fragment as a probe, a 2.1 kb full-length cDNA was isolated from a rat striatal cDNA library. This cDNA encodes a protein of 410 amino acids and is highly homologous to previously isolated adenosine receptor cDNAs. Expression of this cDNA in COS cells revealed high affinity (Kd = 38.6 nM) and saturable binding of the A2 adenosine receptor-selective ligand [3H]CGS 21680. Agonist displacement profile of [3H]CGS 21680 binding was consistent with an adenosine receptor of the A2 subtype (NECA greater than (R)-PIA greater than CPA greater than (S)-PIA). In situ hybridization demonstrated that rat A2 adenosine receptor mRNA was co-expressed in the same striatal neurons as D2 dopamine receptor mRNA, and never co-expressed with striatal D1 dopamine receptor mRNA. Several lines of evidence have previously suggested that dopamine-induced changes in motor behavior can be modulated by adenosine analogs acting at the A2 subtype of adenosine receptor in the forebrain. The co-expression of D2 dopamine and A2 adenosine receptors in a subset of striatal cells provides an anatomical basis for dopaminergic-adenosinergic interactions on motor behavior.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine / analogs & derivatives
  • Adenosine / metabolism
  • Amino Acid Sequence
  • Animals
  • Antihypertensive Agents / metabolism
  • Base Sequence
  • Blotting, Northern
  • Caudate Nucleus / physiology
  • Cell Line
  • Cloning, Molecular
  • Corpus Striatum / physiology*
  • Dogs
  • Gene Library
  • Hypothalamus, Middle / physiology*
  • Kinetics
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides
  • Phenethylamines / metabolism
  • Poly A / genetics
  • Poly A / isolation & purification
  • Polymerase Chain Reaction
  • Putamen / physiology
  • RNA / genetics
  • RNA / isolation & purification
  • RNA, Messenger / analysis
  • RNA, Messenger / metabolism
  • Rats
  • Receptors, Dopamine D2 / genetics*
  • Receptors, Purinergic / genetics*
  • Receptors, Purinergic / metabolism
  • Sequence Homology
  • Transfection


  • Antihypertensive Agents
  • Oligodeoxyribonucleotides
  • Phenethylamines
  • RNA, Messenger
  • Receptors, Dopamine D2
  • Receptors, Purinergic
  • 2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine
  • Poly A
  • RNA
  • Adenosine