Joshua R. Sanes and his Harvard University colleagues compared a synapse known as the skeletal neuromuscular junction in young adult and aged mice. Synapses are the connections that exist between nerve cells or nerves and the muscles that they control. In young neuromuscular synapses, nerve endings match up with their receptors on muscle fibers, enabling efficient transmission of brain signals to the muscle. However, in aged synapses, nerve shrinkage can reduce contact with muscle receptors, leading to muscle wasting.
Dr. Sanes’ team found a variety of age-related differences between the synapses of the young and old mice. However, animals fed a calorie-restricted diet had reductions in these age-associated changes. Additionally, one month of exercise performed by 22-month-old mice partially reversed changes that had already occurred.
Editor’s note: The findings raise the question of whether calorie restriction mimetics might elicit similar benefits.
* Proc Natl Acad Sci. 2010 Aug 17.