Profiling age-related muscle weakness and wasting: neuromuscular junction transmission as a driver of age-related physical decline

This study investigates how the connection between nerves and muscles, called the neuromuscular junction (NMJ), changes with age and contributes to muscle weakness and loss of function. The researchers used electrophysiological tests on aged and young rats to measure the function of the NMJ and correlated these measurements with muscle strength and mass. They found that NMJ dysfunction in aged rats was associated with decreased muscle strength, reduced muscle mass, and impaired muscle contractility, suggesting that the NMJ plays a critical role in age-related muscle decline.

• 1
  Aged rats exhibited significant declines in NMJ transmission stability and reliability, as measured by SFEMG and RNS.
• 2
  NMJ deficits were tightly correlated with hindlimb grip strength, gastrocnemius muscle weight, loss of peak contractility torque, degree of tetanic fade, and motor unit loss.
• 3
  Motor unit number estimation (MUNE) was significantly lower in aged rats in both forelimb and hindlimb muscles, indicating a loss of motor units with age.