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


Physiological changes that lead to skeletal muscle dysfunction and atrophy during aging are poorly understood and thus therapeutic interventions which can combat this condition are limited or ineffective. Prior studies revealed the potential involvement of the neuromuscular junction (NMJ) in this condition and that signaling between the nervous system and skeletal may be responsible for, or at least play a role in, atrophy and functional decline in aged individuals. Authors set out to determine the role the NMJ plays in age-related functional deficits in young and old rats. Multiple measures were made to elucidate physiological changes in transmission at the NMJ, functional indices like grip strength and hindlimb mechanics (1305A) as well as more clinical measures such as SFEMG and RNS. Researchers showed significant disruption of the NMJ which aligned with detriments found in the functional indices, specifically reduced grip strength, peak isometric torque, motor unit number as well as increased gastrocnemius atrophy and tetanic drop off. These results implicate the NMJ as a significant player in skeletal muscle dysfunction with age and as a potential therapeutic target to combat resultant sarcopenia.