Tyrosine improves appetite, cognition, and exercise tolerance in activity anorexia

Area of Science:

• Neuroscience
• Behavioral Science
• Nutritional Science

Background:

• The activity wheel model in mice can induce anorexia.
• Neurochemical changes, including serotonin and dopamine metabolites, are associated with this condition.

Purpose of the Study:

• To investigate the effects of tyrosine supplementation on exercise tolerance, behavior, and brain neurochemistry in mice using a modified activity wheel model.
• To explore tyrosine's potential to counteract activity-induced anorexia and its associated neurochemical alterations.

Main Methods:

• Mice were subjected to a 2-week regimen involving restricted feeding, exercise on a running wheel, and daily injections of either saline or tyrosine.
• Food consumption, cognitive function (eight-arm maze), and brain neurochemistry (adrenergic and serotonergic metabolites) were assessed.

Main Results:

• Activity-induced anorexia led to significant weight loss and decreased food consumption, which tyrosine administration restored.
• Both physical activity and tyrosine improved cognitive performance in the eight-arm maze.
• Tyrosine modulated neurochemical changes in the hypothalamus and hippocampus, including those related to serotonin and dopamine.

Conclusions:

• Tyrosine administration effectively reverses the negative impacts of activity-induced anorexia on food consumption, cognitive behavior, and physical activity.
• These findings suggest that nutritional interventions with tyrosine may be beneficial for treating eating disorders.
• Tyrosine may also enhance exercise tolerance and delay fatigue in non-clinical settings.