Figure 1.

Non-invasive dural application of 10% AITC produces headache-related behaviors in both male and female mice. Dural application of AITC produces cutaneous allodynia in both male ((a), (b)) and female mice ((d), (e)). Withdrawal thresholds to tactile stimuli applied to the face ((a), (d)) and hindpaws ((b), (e)) were measured in animals prior to and after dural application of AITC, vehicle (mineral oil) or a null injection (n = 6 for all groups, see methods for definition of null injections). In males, null injections failed to produce significant facial and hindpaw allodynia at all timepoints ((a), (b)). Administration of AITC produced significant allodynia facial (a) and hindpaw responses (b) in males. In females, administration of AITC produced significant facial allodynia (d) and hindpaw responses (e). Grimace behaviors for both males (n = 6 all groups, (c) and females (n = 6 all groups, (f) were significant at multiple time points. Two-factor analysis of variance (ANOVA) indicated a significant effect of both treatment and time of both the face and hindpaws. Significant differences among means for each group were determined by analysis of variance followed by Bonferroni post hoc test. Males (a) facial: Time F (4, 75) = 6.602, p= 0.0001, treatment F (2, 75) = 6.602, p < 0.0001; (b) hindpaw: Time F (4, 75) = 6.572, p < 0.0001, treatment F (2, 75) = 13.03, p < 0.0001; (c) grimace: Time F (3, 40) = 11.68, P < 0.0001, treatment F (2, 40) = 131.5, P < 0.0001. Females (d) facial: Time F (4, 50) = 5.473, p= 0.001, treatment F (1, 50) = 62.11, p < 0.0001; (e) hindpaw: Time F (4, 50) = 9.213, p < 0.0001, treatment F (1, 50) = 46.4, p < 0.0001; (f) grimace: Time F (3, 28) = 26.75, p < 0.0001, treatment F (1, 28) = 303.8, p < 0.0001.