Analysis of brain indoleamines and catecholamines associated with burn-induced anorexia

Guinea pigs subjected to a full-thickness 30% body surface flame burn significantly reduced food intake and lost weight for 5 days thereafter. Comparison of brain monoamine changes in burned, pair-fed control, and freely feeding control groups revealed normal levels of norepinephrine and elevated concentrations of dopamine in burned animals compared to the pair-fed control group. Levels of the serotonin precursor, tryptophan, and metabolite, 5-hydroxyindoleacetic acid, were also increased in burned compared to pair-fed animals, suggesting increased activity of indoleamine neurons. Although brain catecholamine levels were not correlated with food intake, significant negative correlations between food consumption and tryptophan, serotonin, and 5-hydroxyindoleacetic acid were observed. These data suggest that aberrations in indoleamine and possible catecholamine neurotransmitter systems may be involved in the mediation of burn-induced anorexia.