Effects of acute physical exercise on central serotonergic systems

Medicine & Science in Sports & Exercise. 1997-01-01; 29(1): 58-62
DOI: 10.1097/00005768-199701000-00009

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This paper reviews data concerning the effects of acute physical exercise
(treadmill running) in trained rats. Works from the 1980’s have established that
acute running increases brain serotonin (5-hydroxytryptamine: 5-HT) synthesis in
two ways. Lipolysis-elicited release of free fatty acids in the blood compartment
displaces the binding of the essential amino acid tryptophan to albumin, thereby
increasing the concentration of the so-called « free tryptophan » portion, and
because exercise increases the ratio of circulating free tryptophan to the sum of
the concentrations of the amino acids that compete with tryptophan for uptake at
the blood-brain barrier level, tryptophan enters markedly in the brain
compartment. However, this marked increase in central tryptophan levels increases
only to a low extent brain 5-HT synthesis, as assessed by the analysis of
5-hydroxyindoleacetic acid levels, thereby suggesting that exercise promotes
feedback regulatory mechanisms. Indirect indices of 5-HT functions open the
possibility that acute exercise-induced increases in 5-HT biosynthesis are
associated with (or lead to) increases in 5-HT release. Lastly, the hypothesis
that training and/or acute exercise triggers changes in 5-HT receptors has been
examined in several studies; actually, both positive and negative results have
been reached. Taken together, all these data support the need for future studies
on the functional effects of exercise on 5-HT, including those related to the
hypothesis that the positive mood effects of exercise rely (partly or totally) on
central serotonergic systems.


Auteurs Bordeaux Neurocampus