INHIBITION OF DHPR PREVENTS DECLINE OF M. SOLEUS STRENGTH IN RATS DURING 3-DAY FUNCTIONAL UNLOADING

Muscle atrophy and loss of strength observed in hypokinesia may start soon after functional unloading began. To explore these processes and develop countermeasures, a 3-day suspension experiment was fulfilled with Wistar male rats injected with nifedipine, a blocker of dihydropyridine receptors (DHPR). We used 3 groups with 8 rats in each: suspension (HS), supension + nifedipine (HSN) and control (С). Loss of m. soleus weight by 22 % was found in both suspension groups (p < 0.05). At the same time, DHPR inhibition during 3-day functional unloading prevented strength loss, junctophilin proteolysis, and Са2+ increase in m. soleus myoplasm and mitochondria. Nifedipine injected at the beginning of functional unloading keeps slow postural m. soleus from weakening.