Last week in this column we reported a study showing that exercising four hours after a learning task lead to improvements in memory. The researchers guessed that it might the release of chemicals called catecholamines after exercise that caused the effect. It might well be those catecholamines but according to another new study it might also be due to a protein that is released when you run.
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In the new study researchers found high levels of a protein called cathepsin B in the blood and muscle cells of mice that had been running on an exercise wheel every day for three weeks. Then the researchers found that when cathepsin B was applied to brain cells it triggered the production of brain cell development and growth (neurogensis).
Following on from this the researchers tested two groups of mice; one group that could produce cathepsin B normally in response to exercise and another that could not. Every day for a week both groups of mice were given the Morris water maze test which involved the mice locating a platform within a small pool. The results showed that the normal mice with normal cathepsin B levels could recall the location of the platform where the mice without cathepsin B could not.
This suggests that cathepsin B plays a critical role in memory and therefore exercise does as well. It is another piece in the puzzle of how memory works.
