Increased histidine preference during specific alteration of rhythm of environmental temperature stress in rats

It has been reported that specific alteration of rhythm of environmental temperature (SART) stress induces various physiological changes. In this study, changes in taste preference during SART stress were investigated in rats. Rats were given free access to six amino acid solutions, saline, and water in a choice paradigm. During SART stress, daily food intake increased significantly by 50% whereas the rate of body weight gain decreased significantly to one third that observed during the prestress baseline period. In addition, consumption of histidine solution increased significantly, whereas intakes of water, monosodium glutamate, saline, glycine, arginine, lysine, and threonine were unaffected. Results suggest that a specific preference for histidine emerges during SART stress, which may be related to the stress-induced changes in the histamine turnover in the brain and peripheral tissues.