Adenosine enhances acetylcholine receptor channel openings and intracellular calcium 'spiking' in mouse skeletal myotubes
Aims 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 differenti...
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Published in | Acta Physiologica Vol. 214; no. 4; pp. 467 - 480 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Blackwell Publishing Ltd
01.08.2015
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Aims
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 [Ca2+]i ‘spikes’. The pharmacological characterization of the adenosine receptor‐mediated effects suggested a prevalent involvement of the A2B adenosine receptor subtype.
Conclusion
We propose that the interplay between endogenous adenosine and nicotinic acetylcholine receptors represents a potential novel strategy to improve differentiation/regeneration of skeletal muscle. |
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Bibliography: | istex:56BC8430BFF5C34547B785929AE6047F42DAE0C1 Fondazione Benefica Kathleen Foreman-Casali (Italy) ark:/67375/WNG-8FSPLF3N-H Figure S1. Effect of specific P1-receptor agonists on the mean open time and open probability (Po) of autocrine ACh channels observed in cells pre-incubated with ADA (5 U mL-1, 60 min, at RT). In ADA, the values were 3.95 ± 0.65 ms (n = 20) and 0.0054 ± 0.0018 (n = 24) respectively. In the presence of ADA + CPA (10 nM, at least 30 minutes at RT), a specific agonist for the A1 receptor subtype, no significant effects were observed on the mean open time (6.67 ± 1.72 ms) and Po (0.0045 ± 0.0019, n = 5). Similar results were found in cells pretreated with ADA + the A2AR agonist CGS 21680 (100 nM, at least 30 minutes at RT) or ADA + the A3R agonist AB-MECA (10 nM, at least 30 minutes at RT). In the first case, the mean open time was 5.82 ± 0.84 ms and the Po 0.009 ± 0.0035 (n = 5); in the latter case, the values were 5.84 ± 0.26 (n = 9) and 0.0025 ± 0.0009 (n = 10). Fondazione Beneficentia Stiftung (Liechtenstein) University of Trieste - No. FRA2013 ArticleID:APHA12473 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1748-1708 1748-1716 |
DOI: | 10.1111/apha.12473 |