Under the Hood

More Benefits Of Exercise: Running Releases Protein In Brain That Protects Cognitive Function, Improves Memory

running-1081694_640 Here's why exercise improves cognitive function. Pixabay, public domain

Just last week, a study was published in the Cell Press journal Current Biology that showed how exercising four hours after learning something can help consolidate those memories. There are a number of recent studies suggesting a link between exercise and improved cognitive function, but few give a specific reason as to how it works, until now.

In a recent study, published in Cell Metabolism, researchers led by Henriette van Praag, a neuroscientist at the National Institute on Aging, examined how exercise can improve memory recall. Their findings highlight a clear difference in the cognition between ordinary control mice and mice that lacked a certain protein known as cathepsin B.

“Cathepsin B has been studied mostly in relation to pathological conditions, such as cancer,” van Praag told Medical Daily. “But we wanted to know how it reacts to certain physiological conditions, particularly during exercise.”

Although cathepsin B is secreted by tumors and has been implicated in cell death and the formation of amyloid plaque in the brain, van Praag and her team reference other studies showing how the protein can also be used to protect the brain by clearing amyloid plaques. She believes that, in different amounts and conditions, cathepsin B may have varying effects.

The two groups of mice completed a daily swim test in the Morris water maze. The researchers placed them in a small pool where they learned to swim to a hidden platform below the surface. Mice were also housed either in a standard cage or one with a running wheel for several weeks. The researchers screened for proteins that could be secreted by muscle tissue and transported to the brain. Cathepsin B was considered the most interesting.

After exposing muscle cells grown in a dish to a compound that mimics exercise, the researchers found that cathepsin B production increased. They also discovered high levels of this protein in the blood and muscle cells of mice that ran daily on their exercise wheels. Applying cathepsin B to brain cells in a dish led to a noticeable production of molecules which often lead to neurogenesis, the growth and development of new cells, including neurons.

"We also have converging evidence from our study that cathepsin B is upregulated in blood by exercise for three species — mice, rhesus monkeys, and humans,” said van Praag in a statement. “Moreover, in humans who exercise consistently for four months, better performance on complex recall tasks, such as drawing from memory, is correlated with increased cathepsin B levels."

Looking forward, the researchers hope to understand how cathepsin B breaks the blood-brain barrier, the mechanism by which capillaries carry blood to the brain and spinal cord while obstructing the passage of foreign substances, as well as how it activates neuronal signaling, growth, and connections. They also hope to shed light on how this protein behaves in different species and how its production changes with age. One thing’s for certain, though: It doesn’t work overnight.

"Overall, the message is that a consistently healthy lifestyle pays off," van Praag said. "People often ask us, how long do you have to exercise, how many hours? The study supports that the more substantial changes occur with the maintenance of a long-term exercise regimen."

Source: Moon H, van Praag H, et al. Running-Induced Systemic Cathepsin B Secretion Is Associated with Memory Function Cell Metabolism. Cell Metabolism . 2016.

Loading...