Harvard researchers have uncovered a mechanism through which caloric restriction and exercise delay some of the debilitating effects of aging by rejuvenating the connections between nerves and the muscles that they control.
The research, conducted in the labs of Joshua Sanes and Jeff Lichtman, both members of the Center for Brain Science at Harvard and professors of molecular and cellular biology, begins to explain prior findings that exercise and restricted-calorie diets help to starve off the mental and physical degeneration of aging.
Sanes said their research, conducted through laboratory mice genetically engineered so their nerve cells glow in fluorescent colors, shows that some of the debilitation of aging is caused by the deterioration of connections that nerves make with the muscles they control, structures called neuromuscular junctions. These microscopic links are remarkably similar to the synapses that connect neurons to form information-processing circuits in the brain.
In a healthy neuromuscular synapse, nerve endings and their receptos on muscle fibers are almost a perfect match, like two hands placed together, finger to finger, palm to palm.