Dihydropyridine Receptor Inhibition Attenuates Force and Fiber Cross-Sectional Area Decrease in the Three-Day...

Area of Science:

• Muscle physiology
• Cellular signaling
• Biochemistry

Background:

• Sarcolemma depolarization is an early effect of skeletal muscle unloading.
• Unloading may activate dihydropyridine receptors (DHPR), leading to calcium release and muscle atrophy.

Purpose of the Study:

• To investigate the role of DHPR in unloading-induced skeletal muscle atrophy.
• To evaluate the therapeutic potential of DHPR inhibition for preserving muscle function.

Main Methods:

• Rat soleus muscles were unloaded via hindlimb suspension for three days.
• Nifedipine, a DHPR calcium channel blocker, was administered.
• Muscle contractile properties, ATP, ROS, Ca2+ content, PGC1alpha mRNA, and Junctophilin-1 (JP1) were assessed.

Main Results:

• DHPR inhibition attenuated the decline in muscle contractile properties.
• Nifedipine prevented the accumulation of ATP, ROS, and Ca2+.
• DHPR blockade inhibited JP1 proteolysis and preserved PGC1alpha mRNA levels.

Conclusions:

• DHPR activation contributes to skeletal muscle atrophy during unloading.
• Inhibiting DHPR preserves muscle contractile function and cellular homeostasis.
• DHPR blockers represent a potential therapeutic strategy for inactive muscle preservation.