Serotonin Levels Facilitate Exercise-Induced Neurons

A new study shows the underlying mechanism that involves neurogenesis in specific regions of the brain when exercise occurs.

The process is crucial to serotonin signaling, according to the study by Dr. Friederike Klempin, Daniel Beis and Dr. Natalia Alenina from the research group led by Professor Michael Bader at the Max Delbruck Center (MDC) Berlin-Buch.

Researchers note that the hippocampus plays an important role in learning and in memory and is one of the brain regions where new neurons are generated throughout life.

Researchers demonstrated that mice with the ability to produce serotonin are likely to release more of this hormone during exercise, which in turn increases cell proliferation of precursor cells in the hippocampus. Seeing this, scientists believe that serotonin levels seem to facilitate the transition of stem to progenitor cells that become neurons in the adult mouse brain.

Klempin and Alenina both said they felt that it was surprising that normal baseline neurogenesis occur in mice, due to genetic mutation, and cannot produce serotonin in the brain. However, it has been noted that some of the stem cells in serotonin-deficient mice either die or fail to become neurons.

However, the group of wheel-running mice that do not produce serotonin did not exhibit an exercise-induced increase in neurogenesis. The compensatory mechanism failed following running. The researchers concluded: "Serotonin is not necessarily required for baseline generation of new neurons in the adult brain, but is essential for exercise-induced hippocampal neurogenesis."

 Deficiency in serotonin, popularly known as the "molecule of happiness," has been considered in the context of theories linking major depression to declining neurogenesis in the adult brain. "Our findings could potentially help to develop new approaches to prevent and treat depression as well as age-related decline in learning and memory," researchers said, according to the study.