Figure 2.

Administration of Ucn for 3 d results in increased autonomic and behavioral reactivity to peripheral anxiogenic stimuli such as sodium lactate infusions. Another group of animals primed with Ucn for 3 d demonstrates that they not only show increased baseline anxiety responses but also become reactive to sodium lactate infusions (15 min administration; 10 ml/kg; 0.5 m solution). A–C, The group differences in heart rate (A), respiratory rate (B), and responses (C) in the social interaction test of anxiety before and after priming clearly demonstrate an increased physiological and behavioral reactivity after priming, suggesting greater stress vulnerability. Asterisk, Significantly different from prepriming by paired t test; *p < 0.0001 (n = 6).