Figure 2

Change in the head-withdrawal threshold to mechanical stimulation of the mental skin and whisker pad skin. A: Mechanical head-withdrawal threshold in the mental skin ipsilateral to the sham operation (n = 12) and IAN-X (n = 12), B: Mechanical head-withdrawal threshold in the mental skin contralateral to the sham operation and IAN-X, C: Mechanical head-withdrawal threshold in the mental skin ipsilateral to IAN-X after MC (i.p., n = 12 and m.i., n = 10) and saline (i.p., n = 10 and m.i., n = 10) administration, D: Mechanical head-withdrawal threshold in the mental skin contralateral to IAN-X after MC (i.p., and m.i.,) and saline (i.p., and m.i.,) administration, E: Mechanical head-withdrawal threshold in the whisker pad skin ipsilateral to the sham operation (n = 12) and IAN-X (n = 12), F: Mechanical head-withdrawal threshold in the whisker pad skin contralateral to the sham operation and IAN-X, G: Mechanical head-withdrawal threshold in the whisker pad skin ipsilateral to IAN-X after MC (i.p., n = 12 and m.i., n = 10) and saline (i.p., n = 10 and m.i., n = 10) administration, H: Mechanical head-withdrawal threshold in the whisker pad skin contralateral to IAN-X after MC (i.p., and m.i.,) and saline (i.p., and m.i.,) administration. The arrow in the graph indicates the time point of the sham operation or IAN-X. The behavioral test was assessed once a day for 14 days, and the median value was adopted. It is notable that the mechanical head-withdrawal threshold was significantly decreased 14 days after IAN-X, and administration of MC (both i.p. and m.i.) significantly attenuated the reduction on the head-withdrawal threshold 14 days after IAN-X. Pre: the day before sham or IAN-X, a indicates: pre-IAN-X vs. post-IAN-X, b indicates: sham vs. IAN-X, c indicates: pre-IAN-X + MC (i.p.) vs. post-IAN-X + MC (i.p.), pre-IAN-X + MC (m.i.) vs. post-IAN-X + MC (m.i.), pre-IAN-X + saline (i.p.) vs. post-IAN-X + saline (i.p.), pre-IAN-X + saline (m.i.) vs. post-IAN-X + saline (m.i.), d indicates: IAN-X + MC (i.p.) vs. IAN-X + MC (m.i.), IAN-X + MC (i.p.) vs. IAN-X + saline (i.p.) and IAN-X + MC (i.p.) vs. IAN-X + saline (m.i.), e indicates: IAN-X + MC (m.i.) vs. IAN-X + saline (i.p.) and IAN-X + MC (m.i.) vs. IAN-X + saline (m.i.), p < 0.05 was considered significant (one way ANOVA with Tukey test, and Dunnett’s test for pre vs. post IAN-X or pre vs. post IAN-X + MC or pre vs. post IAN-X + saline).