Visceral hyperalgesia in transgenic mice induced by intracolon injection of capsaicin. Behavioral reactions (abdominal licking, stretching, squashing the lower abdomen against floor and abdominal retractions) evoked by intracolonic injection of vehicle solution or 0.1% capsaicin in WT and Tg mice. A. Number of behaviors observed in each 5 min period over a total observation time of 20 min post-administration. ***Indicates the other three groups which were significantly different from capsaicin-treated Tg mice during the first 5 min observation period (p < 0.001). B. Number of behaviors observed in the total 20 min period post-administration. Data are shown as mean ± s.e.m. (n = 5-11, *p < 0.05, **p < 0.01, ***p < 0.001).