Pharmacological and biochemical characterization of A3 adenosine receptors in Jurkat T cells

Br J Pharmacol. 2001 Sep;134(1):116-26. doi: 10.1038/sj.bjp.0704254.


1. The present work was devoted to the study of A3 adenosine receptors in Jurkat cells, a human leukemia line. 2. The A3 subtype was found by means of RT-PCR experiments and characterized by using the new A3 adenosine receptor antagonist [3H]-MRE 3008F20, the only A3 selective radioligand currently available. Saturation experiments revealed a single high affinity binding site with K(D) of 1.9+/-0.2 nM and B(max) of 1.3+/-0.1 pmol mg(-1) of protein. 3. The pharmacological profile of [3H]-MRE 3008F20 binding on Jurkat cells was established using typical adenosine ligands which displayed a rank order of potency typical of the A3 subtype. 4. Thermodynamic data indicated that [3H]-MRE 3008F20 binding to A3 subtype in Jurkat cells was entropy- and enthalpy-driven, according with that found in cells expressing the recombinant human A3 subtype. 5. In functional assays the high affinity A3 agonists Cl-IB-MECA and IB-MECA were able to inhibit cyclic AMP accumulation and stimulate Ca(2+) release from intracellular Ca(2+) pools followed by Ca(2+) influx. 6. The presence of the other adenosine subtypes was investigated in Jurkat cells. A1 receptors were characterized using [3H]-DPCPX binding with a K(D) of 0.9+/-0.1 nM and B(max) of 42+/-3 fmol mg(-1) of protein. A2A receptors were studied with [3H]-SCH 58261 binding and revealed a K(D) of 2.5+/-0.3 nM and a B(max) of 1.4+/-0.2 pmol mg(-1) of protein. 7. In conclusion, by means of the first antagonist radioligand [3H]-MRE 3008F20 we could demonstrate the existence of functional A3 receptors on Jurkat cells.

MeSH terms

  • Animals
  • Binding, Competitive / drug effects
  • CHO Cells
  • Calcium / metabolism
  • Cricetinae
  • Cyclic AMP / metabolism
  • Dose-Response Relationship, Drug
  • Guanosine Triphosphate / pharmacology
  • Humans
  • Jurkat Cells
  • Kinetics
  • Phenylurea Compounds / metabolism
  • Phenylurea Compounds / pharmacology
  • Purinergic P1 Receptor Agonists
  • Pyrimidines / metabolism
  • Pyrimidines / pharmacology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptor, Adenosine A2A
  • Receptor, Adenosine A3
  • Receptors, Purinergic P1 / genetics*
  • Receptors, Purinergic P1 / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • T-Lymphocytes / cytology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / metabolism*
  • Thermodynamics
  • Time Factors
  • Triazoles / metabolism
  • Triazoles / pharmacology
  • Tritium
  • Xanthines / metabolism
  • Xanthines / pharmacology


  • 5-amino-7-(2-phenylethyl)-2-(2-furyl)pyrazolo(4,3-e)-1,2,4-triazolo(1,5-c)pyrimidine
  • MRE 3008-F20
  • Phenylurea Compounds
  • Purinergic P1 Receptor Agonists
  • Pyrimidines
  • RNA, Messenger
  • Receptor, Adenosine A2A
  • Receptor, Adenosine A3
  • Receptors, Purinergic P1
  • Triazoles
  • Xanthines
  • Tritium
  • Guanosine Triphosphate
  • 1,3-dipropyl-8-cyclopentylxanthine
  • Cyclic AMP
  • Calcium