Abstract
Exercise-induced translocation of Na+-K+ pump subunits to the sarcolemmal membrane was studied using sarcolemmal giant vesicles as a membrane purification procedure. The subunit content was quantified by Western blotting or by ouabain labeling. Low-intensity treadmill running increased (P<0.01) the alpha1, alpha2, beta1, and beta2 subunit contents by 19-32% in membranes from oxidative muscle fibers and the alpha1, alpha2, and beta2 contents increased by 13-25% in membranes from glycolytic muscle fibers. Ouabain labeling of membranes from mixed fibers was increased by 29% after exercise. A similar increase in subunit content could be induced by 5 min of fatiguing, high-intensity electrical stimulation of isolated soleus muscles. An increased subunit content was just detectable in vesicles produced 30 min after exercise, and the content was completely back to control levels 3 h after exercise. It is concluded that both low-intensity long-lasting running and short-lasting high-intensity contractions are able to induce a translocation of pump subunits to the sarcolemmal membrane. The post-exercise disappearance of the extra subunits (half-time approximately 20 min) from the membrane demonstrates the reversible nature of the translocation process.
| Original language | English |
|---|---|
| Journal | Pflügers Archiv - European Journal of Physiology |
| Volume | 443 |
| Issue number | 2 |
| Pages (from-to) | 212-7 |
| Number of pages | 6 |
| ISSN | 0031-6768 |
| DOIs | |
| Publication status | Published - Nov 2001 |
Keywords
- Animals
- Biological Transport
- Cell Membrane/metabolism
- Electric Stimulation
- Glycolysis
- Male
- Motor Activity/physiology
- Muscle, Skeletal/metabolism
- Ouabain/metabolism
- Oxidation-Reduction
- Rats
- Rats, Wistar
- Sodium-Potassium-Exchanging ATPase/metabolism
- Time Factors