Amino Acid Analysis Demonstrates that Increased Plasma Free Tryptophan Causes the Increase of Brain Tryptophan During Exercise in the Rat |
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| Authors: | Francis Chaouloff Guy A Kennett Bernard Serrurrier Daniele Merino Gerald Curzon |
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| Institution: | Department of Pharmacology, INSERM U7, CHU Necker-Enfants Malades, Paris, France;Department of Neurochemistry, Institute of Neurology, London, England;CERMA-LCBA, Department of Metabolic Physiology, Paris, France |
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| Abstract: | Rats were trained to run on a horizontal treadmill for 2 h at 20 m/min. This activity considerably increased plasma free tryptophan (TRP) (+70%) but did not alter plasma total TRP levels and had little or no effect on plasma concentrations of the other large neutral amino acids (LNAAs) that compete with TRP for entry into the brain. Brain TRP levels increased by 80%. The only other brain LNAA to be affected by exercise was threonine, which rose moderately. The results indicate that increased plasma free TRP was specifically responsible for the increase of brain TRP after 2 h of exercise. Brain lysine was also increased whereas glycine, alanine, and gamma-aminobutyric acid were decreased. The differences between the present findings and those previously obtained following 2 h immobilization stress are discussed. |
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| Keywords: | Amino acids Tryptophan Exercise |
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