[EFFECT OF SHORT-TERM DRY IMMERSION ON PROTEOLYTIC SIGNALING IN HUMAN SOLEUS MUSCLE]

The signaling processes initiating proteolytic events in m. soleus of humans during short-term exposure in the non-weight bearing conditions were analyzed. Dry immersion (DI) was used to induce weight deprivation over 3 days. Western blotting was used to define the IRS-1 content, total and phosphorylated neuronal NO-synthase (nNOS), AMP-activated protein kinase (AMPK) that control the anabolic and catabolic pathways, and concentrations of cytoskeletal protein desmin and Ca²⁺-activated protease calpin. Already on day-3 of DI calpain-dependent proteolysis manifests itself by reductions in both the total content and level of nNOS phosphorilation. Moreover, AMPK phosphorilation was decreased drastically.