title: Adenosine enhances acetylcholine receptor channel openings and intracellular calcium 'spiking' in mouse skeletal myotubes.
abstract: OBJECTIVE
  The autocrine activity of the embryonic isoform of the nicotinic acetylcholine receptor is crucial for the correct differentiation and trophism of skeletal muscle cells before innervation. The functional activity of extracellular adenosine and adenosine receptor subtypes expressed in differentiating myotubes is still unknown. In this study, we performed a detailed analysis of the role of adenosine receptor-mediated effects on the autocrine-mediated nicotinic acetylcholine receptor channel openings and the associated spontaneous intracellular calcium 'spikes' generated in differentiating mouse myotubes in vitro.
  
  
  METHODS
  Cell-attached patch-clamp recordings and intracellular calcium imaging experiments were performed in contracting myotubes derived from mouse satellite cells.
  
  
  RESULTS
  The endogenous extracellular adenosine and the adenosine receptor-mediated activity modulated the properties of the embryonic isoform of the nicotinic acetylcholine receptor in myotubes in vitro, by increasing the mean open time and the open probability of the ion channel, and sustaining nicotinic acetylcholine receptor-driven intracellular [Ca(2+) ]i 'spikes'. The pharmacological characterization of the adenosine receptor-mediated effects suggested a prevalent involvement of the A2B adenosine receptor subtype.
  
  
  CONCLUSIONS
  We propose that the interplay between endogenous adenosine and nicotinic acetylcholine receptors represents a potential novel strategy to improve differentiation/regeneration of skeletal muscle.
authors: Department of Life Sciences, University of Trieste, via A. Fleming 22, Trieste, I-34127, Italy.|B.R.A.I.N. Centre for Neuroscience, via Fleming 22, Trieste, I-34127, Italy.
authors: A
authors: A
authors: Bernareggi
authors: Department of Life Sciences, University of Trieste, via A. Fleming 22, Trieste, I-34127, Italy.|B.R.A.I.N. Centre for Neuroscience, via Fleming 22, Trieste, I-34127, Italy.
authors: E
authors: E
authors: Luin
authors: Department of Life Sciences and Biotechnology, University of Ferrara, Via L. Borsari 46, Ferrara, I-44121, Italy.
authors: B
authors: B
authors: Pavan
authors: Department of Life Sciences, University of Trieste, via A. Fleming 22, Trieste, I-34127, Italy.|B.R.A.I.N. Centre for Neuroscience, via Fleming 22, Trieste, I-34127, Italy.
authors: G
authors: G
authors: Parato
authors: Department of Life Sciences, University of Trieste, via A. Fleming 22, Trieste, I-34127, Italy.|B.R.A.I.N. Centre for Neuroscience, via Fleming 22, Trieste, I-34127, Italy.
authors: M
authors: M
authors: Sciancalepore
authors: Department of Life Sciences, University of Trieste, via A. Fleming 22, Trieste, I-34127, Italy.
authors: R
authors: R
authors: Urbani
authors: Department of Life Sciences, University of Trieste, via A. Fleming 22, Trieste, I-34127, Italy.|B.R.A.I.N. Centre for Neuroscience, via Fleming 22, Trieste, I-34127, Italy.
authors: P
authors: P
authors: Lorenzon
mesh_terms: D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D002478:Cells, Cultured; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011978:Receptors, Nicotinic / Q000378:metabolism*
chemical_list: D011978:Receptors, Nicotinic; D000241:Adenosine; D002118:Calcium
keywords: acetylcholine receptor; adenosine; myotubes; patch clamp; skeletal muscle