Premium
Denervation versus pre‐ and postsynaptic muscle immobilization: Effects On acetylcholine‐ and muscle‐specific tyrosine kinase receptors
Author(s) -
Kramer Christopher,
Zoubaa Saida,
Kretschmer Alexander,
Jordan Denis,
Blobner Manfred,
Fink Heidrun
Publication year - 2017
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.25159
Subject(s) - postsynaptic potential , acetylcholine receptor , denervation , neuromuscular junction , endocrinology , medicine , neuromuscular transmission , diaphragm (acoustics) , tyrosine hydroxylase , biology , acetylcholine , chemistry , anatomy , receptor , neuroscience , physics , acoustics , loudspeaker , dopamine
Functional immobility of the diaphragm by mechanical ventilation impairs neuromuscular transmission and may result in ventilator‐induced diaphragmatic dysfunction. We compared 3 diaphragmatic immobilization models with respect to their effects on expression of adult and fetal acetylcholine receptors (AChRs), muscle‐specific receptor tyrosine kinase (MuSK), and muscle fiber morphology. Methods Diaphragms of rats were immobilized by either: (1) phrenicotomy; (2) presynaptic tetrodotoxin nerve blockade; or (3) postsynaptic polyethylene orthosis. AChR subtypes and MuSK were quantified by Western blot and immunohistochemistry. Muscle fiber morphology was evaluated by hematoxylin–eosin staining. Results Adult AChRs remained unchanged, whereas fetal AChRs and MuSK were upregulated in all models. Denervation induced the strongest changes in muscle morphology. Conclusions Each diaphragm immobilization model led to severe morphologic and postsynaptic receptor changes. Postsynaptic polyethylene orthosis, a new model with an intact and functioning motor unit, best reflects the clinical picture of a functionally immobilized diaphragm. Muscle Nerve 55 : 101–108, 2017