It has long been known that regular exercise can help overcome the effects of depression. However the reason for this have been not been clear.
Recent research from the Karolinska Instituet in Stockholm, Sweden has shed some light on the problem.
A protein, PGC-1alpha1, increases in muscle after exercise and helps the beneficial muscle conditioning caused by physical activity.
During the study a group of mice genetically modified to have high levels of PGC-1alpha1 were compared to normal control mice.
Both groups were subjected to a stressful environment of loud noises, flashing lights and reversed circadian rhythm at irregular intervals.
After 5 weeks of mild stress the normal mice had developed depressive behaviour whereas the genetically modified mice did not.
Jorge Ruas, the principal investigator at the Dpt. of Physiology and Pharmacology, stated that they found that the genetically modified mice also produced an enzyme that purges the body of harmful substances. Thus the muscle was acting in a manner analogous to the liver or kidneys.
The enzyme is called KAT. It converts a substance, kynurenine, into kynurenic acid that is not able to pass from the blood into the brain.
The researchers later showed that normal mice when given kynurenine displayed depressive behaviour; whereas the mice with high levels of PGC-1alpha1 were not affected. Indeed these animals did not even show raised levels of kyurenine, as the increased KAT enzymes quickly broke it down to kyurenic acid.
Maria Lindskog of the Dpt. of Neuroscience said that this study represents another piece in the puzzle of understanding in neurobiological terms what depression is.
Agudelo L, Femenía T, Ruas J, et al.
Skeletal Muscle PGC-1α1 Modulates Kynurenine Metabolism and Mediates Resilience to Stress-Induced Depression.
Cell , September 25, 2014;159(1):33-45.
This article was written by Cloud Psychology