2021 Volume 58 Issue 1 Pages 25-31
The mesocortico-limbic system plays critical roles in transforming emotion into behavior and peripheral autonomic responses. In chronic pain states and chronic stress, this system falls into dysfunction and produces various psychosomatic symptoms. However, voluntary exercise can normalize its function and effectively reduce these symptoms. As a possible mechanism, we hypothesized that the amygdala plays an important role in this process. We investigated the effects of voluntary running on the basal amygdala (BA) and the central nuclei of the amygdala (CeA), using partial sciatic nerve ligation (PSL) model mice. The number of activated glutamate (Glu) neurons in the medial BA (medBA) was significantly increased in PSL-Runner mice. A combined immunohistochemical and tracer experiment demonstrated that these activated Glu neurons in the medBA project into the nucleus accumbens lateral shell. Furthermore, in all subdivisions of the CeA, the number of activated gamma-aminobutyric acid (GABA) neurons was dramatically increased in PSL-Sedentary mice, whereas these numbers were significantly decreased in PSL-Runner mice. Therefore, we conclude that exercise-induced normalization of the mesocortico-limbic system may be induced, at least in part, via plastic changes in the amygdala, and that pursuing an active life-style is essential for the improvement of our QOL. The mesocortico-limbic system plays critical roles in transforming emotion into behavior and peripheral autonomic responses. In chronic pain states and chronic stress, this system falls into dysfunction and produces various psychosomatic symptoms. However, voluntary exercise can normalize its function and effectively reduce these symptoms. As a possible mechanism, we hypothesized that the amygdala plays an important role in this process. We investigated the effects of voluntary running on the basal amygdala (BA) and the central nuclei of the amygdala (CeA), using partial sciatic nerve ligation (PSL) model mice. The number of activated glutamate (Glu) neurons in the medial BA (medBA) was significantly increased in PSL-Runner mice. A combined immunohistochemical and tracer experiment demonstrated that these activated Glu neurons in the medBA project into the nucleus accumbens lateral shell. Furthermore, in all subdivisions of the CeA, the number of activated gamma-aminobutyric acid (GABA) neurons was dramatically increased in PSL-Sedentary mice, whereas these numbers were significantly decreased in PSL-Runner mice. Therefore, we conclude that exercise-induced normalization of the mesocortico-limbic system may be induced, at least in part, via plastic changes in the amygdala, and that pursuing an active life-style is essential for the improvement of our QOL.
