Daily Exercise and Stress on Brain Function pp. 23-48
Authors: Den'etsu Sutoo and Kayo Akiyama
Abstract: The effects of exercise and stress on brain function were reviewed through previous reports concerning the calcium-dependent dopamine (DA) synthesizing mechanism. These reports indicate that peripheral calcium is transported to the brain via the blood, thereby enhancing calmodulin (CaM) activity, and the CaM-dependent system subsequently increases DA synthesis in the neostriatum and nucleus accumbens through the phosphorylation of tyrosine hydroxylase (TH) by calcium/CaM-dependent protein kinase II (CaMKII). On the basis of these fundamental studies, the effects of exercise on brain function were investigated. Exercise stimulates calcium metabolic hormone and increases blood calcium levels, thereby increasing DA synthesis in the brain. Subsequently, increased DA levels regulate various brain functions. Therefore, exercise-induced stimulation of calcium-dependent DA synthesis might be a mechanism by which exercise modifies brain function. Also, this mechanism might underlie the rectifying effect of exercise on the symptoms of various diseases such as hypertension, Parkinson's disease, dementia with Lewy bodies, epilepsy, and attention-deficit/hyperactivity disorder. Music also stimulates this pathway. Daily exercise produces a refreshing feeling, reduces blood pressure, and activates other physiologic functions through this pathway; however, excessive exercise, physical fatigue, or stress abnormally enhance DA synthesis and induce physiologic disorders such as depression and gastric ulcer formation. Abnormal acceleration of the calcium-dependent DA synthesizing system induced by heavy stress is alleviated by certain drugs.