One of the main questions I haven’t found a satisfying answer to yet is whether denervation/renervation is causal for sarcopenia. Apparently a huge amount of resources went into imaging neuromuscular junctions for a while—the physiological reviews article I linked spends half the article on the topic—but that seems to be driven by historical accident more than anything. After wading through a ton of it I still haven’t seen any decisive evidence on whether denervation is the main cause of muscle atrophy, or muscle atrophy causes nerve atrophy. It sounds like either is sufficient to cause the other experimentally, but it’s not clear which actually comes first in aging. (And of course research is made difficult by authors sometimes making statements about causality which their data/experimental procedure doesn’t actually establish.)
One of the main questions I haven’t found a satisfying answer to yet is whether denervation/renervation is causal for sarcopenia. Apparently a huge amount of resources went into imaging neuromuscular junctions for a while—the physiological reviews article I linked spends half the article on the topic—but that seems to be driven by historical accident more than anything. After wading through a ton of it I still haven’t seen any decisive evidence on whether denervation is the main cause of muscle atrophy, or muscle atrophy causes nerve atrophy. It sounds like either is sufficient to cause the other experimentally, but it’s not clear which actually comes first in aging. (And of course research is made difficult by authors sometimes making statements about causality which their data/experimental procedure doesn’t actually establish.)