Figure 4

Lack of sensitization within single mechanosensitivity tests in mice conducted using up-down methods. (A) Observed frequency of each possible response pattern when 9 von Frey presentations were used in a test and the corresponding difference in the PWT estimates for each pattern as calculated using the method of Chaplan et al. [3] and SUDO. (B) Negative correlation between the magnitude of the difference in PWT estimates calculated using the two methods and the frequency with which each pattern occurred. (C) Probability of a positive nocifensive response by a mouse to the fifth through ninth von Frey filament presentation in all trials. Data in (C) are mean and 95% confidence interval. (D) PWT estimates measured in mice at baseline (n = 58), 3 hours after intraplantar injection of capsaicin (Cap; 5 μl, 0.5% w/v, n = 12), and 3 hours or 3 days after intraplantar injection of complete Freund’s adjuvant (CFA; 10 μl, n = 12) using the method of Chaplan et al. [3] and SUDO. The two testing methods were presented in a randomized crossover manner in each condition. PWT estimates were not significantly different between methods. (E) Same data as in (D) with PWT estimated expressed as force (g). PWT estimates were not significantly different between methods. Data in (D) and (E) are mean ± s.e.m.