title: Characterization of adenosine receptors in bovine chondrocytes and fibroblast-like synoviocytes exposed to low frequency low energy pulsed electromagnetic fields.
abstract: OBJECTIVE
  The present study describes the presence and binding parameters of the A1, A2A, A2B and A3 adenosine receptors in bovine chondrocytes and fibroblast-like synoviocytes. The effect of low frequency low energy pulsed electromagnetic fields (PEMFs) on the adenosine receptor affinity and density was studied.
  
  
  METHODS
  Saturation, competition binding experiments and Western blotting assays in the absence and in the presence of PEMFs on the adenosine receptors in bovine chondrocytes or fibroblast-like synoviocytes were performed. Thermodynamic analysis of the A2A or A3 binding was studied to investigate the forces driving drug-receptor coupling. In the adenylyl cyclase and proliferation assays the potency of typical high-affinity A2A or A3 agonists in the absence and in the presence of PEMFs was evaluated.
  
  
  RESULTS
  Bovine chondrocytes and fibroblast-like synoviocytes expressed all adenosine receptors. PEMFs evoked an up-regulation of A2A and A3 receptors and thermodynamic parameters indicate that adenosine binding is enthalpy and entropy driven. In PEMF-treated cells the potency of typical A2A or A3 agonists on cyclic AMP assays was significantly increased when compared with the untreated cells. PEMFs potentiated the effect of A2A or A3 agonists on cell proliferation in both cell types.
  
  
  CONCLUSIONS
  PEMFs mediate an up-regulation of A2A and A3 receptors related to an increase of their functional activities in bovine chondrocytes and fibroblast-like synoviocytes. No differences are present in adenosine affinity and in the drug-receptor interactions. Our data could be used as a trigger to future studies addressed to PEMFs and adenosine therapeutic intervention in inflammatory joint diseases.
authors: Department of Clinical and Experimental Medicine, University of Ferrara, Italy.
authors: K
authors: K
authors: Varani
authors: M
authors: M
authors: De Mattei
authors: F
authors: F
authors: Vincenzi
authors: S
authors: S
authors: Gessi
authors: S
authors: S
authors: Merighi
authors: A
authors: A
authors: Pellati
authors: A
authors: A
authors: Ongaro
authors: A
authors: A
authors: Caruso
authors: R
authors: R
authors: Cadossi
authors: P A
authors: PA
authors: Borea
mesh_terms: D000818:Animals; D001168:Arthritis / Q000503:physiopathology / Q000628:therapy; D001667:Binding, Competitive / Q000502:physiology*; D015153:Blotting, Western; D002417:Cattle; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D003627:Data Interpretation, Statistical; D004574:Electromagnetic Fields; D005347:Fibroblasts; D066298:In Vitro Techniques; D010641:Phenotype; D058906:Purinergic P1 Receptor Agonists; D018047:Receptors, Purinergic P1 / Q000032:analysis / Q000378:metabolism*; D013582:Synovial Fluid / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics; D015854:Up-Regulation
chemical_list: D058906:Purinergic P1 Receptor Agonists; D018047:Receptors, Purinergic P1; D000242:Cyclic AMP