CONICET | Buscador de Institutos y Recursos Humanos

Glucocorticoids participate in the behavioral and physiological responses generated under stressful circumstances comingfrom diferent sources?physical and/or psychological. In mammals, the increases of these hormones are mediated by theactivation of the hypothalamic?pituitary?adrenal axis. This response occurs after exposure to novel and unpredictable situations that lead to the loss of homeostasis, for example, a direct encounter with predators or their cues. However, the relationship between the physiological and behavioral responses is still a complex issue in vertebrates. We evaluate the efects of anexperimental manipulation of glucocorticoid levels on the generation of the behavioral and physiological response to stressby predation in the subterranean rodent C. talarum. We found that when tuco-tucos encountered predator cues?fur odor,and largely, immobilization?they responded physiologically by secreting cortisol. This response was accompanied by anassociated behavioral response. However, when the increase in plasma cortisol originated exogenously by the injection ofcortisol, a behavioral response was not observed. Finally, inhibition of glucocorticoids? synthesis was efective in weakening the behavioral efects produced by immobilization. In conclusion, in tuco-tucos, predator cues act as stress factors thattrigger diferential increases in plasma cortisol and a behavioral response associated with the appearance of anxiety states.