Effects of Glutamine and Alanine Supplementation on Central Fatigue Markers in Rats Submitted to Resistance Training

• Published in: Nutrients Vol. 10; no. 2; p. 119
• Main Authors: Coqueiro, Audrey Yule, Raizel, Raquel, Bonvini, Andrea, Hypólito, Thaís, Godois, Allan da Mata, Pereira, Jéssica Ramos Rocha, Garcia, Amanda Beatriz de Oliveira, Lara, Rafael de Souza Bittencourt, Rogero, Marcelo Macedo, Tirapegui, Julio
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25.01.2018; MDPI
• Subjects: Alanine; Alanine - pharmacology; Amino acids; Ammonia; Ammonia - metabolism; Animals; Blood Glucose - metabolism; central fatigue; Dietary Supplements; Dipeptides - blood; Dopamine; Dopamine - blood; Fatigue; Fatigue - blood; Fatigue - drug therapy; Fatty Acids, Nonesterified - blood; Free form; Glutamine; Glutamine - pharmacology; Glycogen; Glycogen - metabolism; Hypothalamus; Liver; Liver - drug effects; Liver - metabolism; Male; Markers; mental fatigue; Muscle, Skeletal - drug effects; Muscle, Skeletal - metabolism; Muscles; Parameters; Physical Conditioning, Animal; Rats; Rats, Wistar; Resistance training; Serotonin; Serotonin - blood; Strength training; Tryptophan; fatigue; resistance training; alanine; mental fatigue; glutamine; central fatigue
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu10020119

Recent evidence suggests that increased brain serotonin synthesis impairs performance in high-intensity intermittent exercise and specific amino acids may modulate this condition, delaying fatigue. This study investigated the effects of glutamine and alanine supplementation on central fatigue markers in rats submitted to resistance training (RT). Wistar rats were distributed in: sedentary (SED), trained (CON), trained and supplemented with alanine (ALA), glutamine and alanine in their free form (G + A), or as dipeptide (DIP). Trained groups underwent a ladder-climbing exercise for eight weeks, with progressive loads. In the last 21 days, supplementations were offered in water with a 4% concentration. Albeit without statistically significance difference, RT decreased liver glycogen, and enhanced the concentrations of plasma glucose, free fatty acids (FFA), hypothalamic serotonin, and ammonia in muscle and the liver. Amino acids affected fatigue parameters depending on the supplementation form. G + A prevented the muscle ammonia increase by RT, whereas ALA and DIP augmented ammonia and glycogen concentrations in muscle. DIP also increased liver ammonia. ALA and G + A reduced plasma FFA, whereas DIP increased this parameter, free tryptophan/total tryptophan ratio, hypothalamic serotonin, and the serotonin/dopamine ratio. The supplementations did not affect physical performance. In conclusion, glutamine and alanine may improve or impair central fatigue markers depending on their supplementation form.