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Anti-aging effects may lie in nerve synapses

Los Angeles Times Staff Writer

Two strategies have been shown in some studies to increase longevity: regular exercise and calorie-restricted diets. How those strategies actually alter human biology to slow aging and improve health remains unknown. However, a new study suggests the effects of exercise and calorie-restriction may occur in nerve synapses.

Researchers at Harvard University examined mice that were genetically engineered so their nerve cells glowed in fluorescent colors. Some mice were placed on a restricted-calorie diet while others were put on a one-month exercise regimen.

The study concluded that some of the aging body's breakdown is due to deterioration in the connections that nerves make with the muscles they control, called neuromuscular junctions.  As people age, the neuromuscular synapses don't fit together as tightly, resulting in less efficient nerve transmission and causing muscles to become weaker. In the study, however, the mice on calorie-restricted diets showed reversal of the deterioration in their neuromuscular junctions. The mice on a one-month exercise regimen were already elderly at the start of the study but still showed some reversal of damage in the synapses.

"Caloric restriction and exercise have numerous, dramatic effects on our mental acuity and motor ability," a coauthor of the study, Joshua Sanes, said in a news release. "This research gives us a hint that the way these extremely powerful lifestyle factors act is by attenuating or reversing the decline in our synapses."

Neuromuscular junctions strongly mimic the synapses in the brain that link neurons. Thus, future research will focus on whether similar effects from calorie restriction and regular exercise occur in the brain.

The study was released in the Proceedings of the National Academy of Sciences.

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