Increased expression of the nicotinic acetylcholine receptor in stimulated muscle.
Chronic low-frequency stimulation has been used as a model for investigating responses of skeletal muscle fibres to enhanced neuromuscular activity under conditions of maximum activation. Fast-to-slow isoform shifting of markers of the sarcoplasmic reticulum and the contractile apparatus demonstrated successful fibre transitions prior to studying the effect of chronic electro-stimulation on the expression of the nicotinic acetylcholine receptor. Comparative immunoblotting revealed that the alpha- and delta-subunits of the receptor were increased in 10-78 day stimulated specimens, while an associated component of the surface utrophin-glycoprotein complex, beta-dystroglycan, was not drastically changed in stimulated fast skeletal muscle. Previous studies have shown that electro-stimulation induces degeneration of fast glycolytic fibres, trans-differentiation leading to fast-to-slow fibre transitions and activation of muscle precursor cells. In analogy, our results indicate a molecular modification of the central functional unit of the post-synaptic muscle surface within existing neuromuscular junctions and/or during remodelling of nerve-muscle contacts.
O'Reilly
Clare
C
Department of Pharmacology, University College Dublin, Belfield, Dublin 4, Ireland.
Pette
Dirk
D
Ohlendieck
Kay
K
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D000252:Calcium-Transporting ATPases / Q000032:analysis; D003598:Cytoskeletal Proteins / Q000032:analysis; D004558:Electric Stimulation; D015151:Immunoblotting; D008565:Membrane Proteins / Q000032:analysis; D018485:Muscle Fibers, Skeletal / Q000737:chemistry / Q000378:metabolism; D009124:Muscle Proteins / Q000032:analysis; D018482:Muscle, Skeletal / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000737:chemistry / Q000378:metabolism*; D011233:Precipitin Tests; D020033:Protein Isoforms / Q000032:analysis; D021122:Protein Subunits; D011817:Rabbits; D011978:Receptors, Nicotinic / Q000096:biosynthesis* / Q000276:immunology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D049411:Utrophin
D015415:Biomarkers; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D020033:Protein Isoforms; D021122:Protein Subunits; D011978:Receptors, Nicotinic; D049411:Utrophin; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases