Effect of intracerebroventricular (i.c.v.) administration of KCNQ channel modulators on visceral pain induced by acetic acid in wild type mice. The onset (A) and the total number of writhes (B) after induction of visceral pain by 0.6% acetic acid (i.p.) were determined over a period of 15 min with XE991, retigabine (RTG) or vehicle administered by i.c.v. injection. XE991 (30 nmol) significantly increased the number of writhes, and RTG (49 nmol) reversed its effect. Data are expressed as mean ± s.e.m (n = 7-13, *p < 0.05).