Effects of electrical stimulation and insulin on Na+–K+-ATPase ([3H]Ouabain Binding) in rat skeletal muscle

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McKenna, Michael ORCID: 0000-0001-9998-0093, Gissel, Hanne and Clausen, Torben (2003) Effects of electrical stimulation and insulin on Na+–K+-ATPase ([3H]Ouabain Binding) in rat skeletal muscle. The journal of physiology, 547 (2). 567 -580. ISSN 00223751


Exercise has been reported to increase the Na+–K+-ATPase (Na+–K+ pump) α2 isoform in the plasma membrane 1.2- to 1.9-fold, purportedly reflecting Na+–K+ pump translocation from an undefined intracellular pool. We examined whether Na+–K+ pump stimulation, elicited by muscle contraction or insulin, increases the plasma membrane Na+–K+ pump content ([3H]ouabain binding) in muscles from young rats. Stimulation of isolated soleus muscle for 10 s at 120 Hz caused a rapid rise in intracellular Na+ content, followed by an 18-fold increase in the Na+ re-extrusion rate (80 % of theoretical maximum). Muscles frozen immediately or 120 s after 10–120 s stimulation showed 10–22 % decrease in [3H]ouabain binding expressed per gram wet weight, but with no significant change expressed per gram dry weight. In soleus muscles from adult rats, [3H]ouabain binding was unaltered after 10 s stimulation at 120 Hz. Extensor digitorum longus (EDL) muscles stimulated for 10–60 s at 120 Hz showed no significant change in [3H]ouabain binding. Insulin (100 mU ml−1) decreased intracellular Na+ content by 27 % and increased 86Rb uptake by 23 % soleus muscles, but [3H]ouabain binding was unchanged. After stimulation for 30 s at 60 Hz soleus muscle showed a 30% decrease in intracellular Na+ content, demonstrating increased Na+–K+ pump activity, but [3H]ouabain binding measured 5 to 120 min after stimulation was unchanged. Stimulation of soleus or EDL muscles for 120–240 min at 1 Hz (continuously) or 10 Hz (intermittently) produced no change in [3H]ouabain binding per gram dry weight. In conclusion, the stimulating effects of electrical stimulation or insulin on active Na+, K+-transport in rat skeletal muscle could not be even partially accounted for by an acute increase in the content of functional Na+–K+ pumps in the plasma membrane.

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Item type Article
URI https://vuir.vu.edu.au/id/eprint/1100
DOI 10.1113/jphysiol.2003.034512
Official URL http://www.blackwell-synergy.com/doi/full/10.1113/...
Subjects Historical > RFCD Classification > 240000 Physical Sciences
Historical > RFCD Classification > 320000 Medical and Health Sciences
Historical > Faculty/School/Research Centre/Department > Centre for Ageing, Rehabilitation, Exercise & Sport Science (CARES)
Keywords electrical stimulation, insulin, Na+-K+-ATPase ([3H]ouabain binding), exercise
Citations in Scopus 45 - View on Scopus
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