Figure 2

Subcutaneous injection of capsaicin increased USVs selectively at 50 kHz. A, Representative trace of USVs at 30, 50, 90, and 120 Hz for saline and capsaicin injected mice. B, USVs at each frequency for mice injected with saline (hatched bars, n = 19) or capsaicin (black bars, n = 16); capsaicin significantly increased USVs at 50 kHz over saline injected mice (p < 0.001). C, Distance traveled in control (white bar), saline (hatched bar) and capsaicin-injected mice (black bar) for 30 min, significant reduction in locomotion were observed with saline and capsaicin (p < 0.01). D, Distance traveled presented in five minute blocks over 30 min. Activity is significantly reduced in capsaicin injected mice during the last five minutes when compared to saline and control mice (p < 0.001). Error bars represent S.E.M.