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Sustained sarcolemma depolarization due to loss of the Na,K-ATPase function is char-acteristic for skeletal muscle motor dysfunction. Ouabain, a specific ligand of the Na,K-ATPase, has a circulating endogenous analogue. We hypothesized that the Na,K-ATPase targeted by the elevated level of circulating ouabain modulates skeletal muscle electrogenesis and prevents its dis-use-induced disturbances. Isolated soleus muscles from rats intraperitoneally injected with oua-bain alone or subsequently exposed to muscle disuse by 6-h hindlimb suspension (HS) were stud-ied. Conventional electrophysiology, Western blotting, and confocal microscopy with cytochemis-try were used. Acutely applied 10 nM ouabain hyperpolarized the membrane. However, a single injection of ouabain (1 µg/kg) prior HS was unable to prevent the HS-induced membrane depo-larization. Chronic administration of ouabain for four days did not change the α1 and α2 Na,K-ATPase protein content, however it partially prevented the HS-induced loss of the Na,K-ATPase electrogenic activity and sarcolemma depolarization. These changes were associated with increased phosphorylation levels of AMP-activated protein kinase (AMPK), its substrate ac-etyl-CoA carboxylase and p70 protein, accompanied with increased mRNA expression of inter-leikin-6 (IL-6) and IL-6 receptor. Considering the role of AMPK in regulation of the Na,K-ATPase, we suggest an IL-6/AMPK contribution to prevent the effects of chronic ouabain under skeletal muscle disuse.
Original language | English |
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Article number | 3920 |
Number of pages | 18 |
Journal | International Journal of Molecular Sciences |
Volume | 22 |
Issue number | 8 |
DOIs | |
State | Published - 10 Apr 2021 |
ID: 77796425