Fig. 2.
Mechanical paw withdrawal latencies and the lack of concentration-dependent antinociceptive effect of menthol. A: von Frey paw withdrawal threshold: ipsilateral hindpaw. The 0.1–10% menthol groups were not significantly different from vehicle (10% ethanol). Only the 40% menthol group was significantly different from all other groups (*: p<0.05, repeated measures ANOVA) indicating allodynia. Data for 0.01% menthol are similar to 0.1% menthol treated groups and omitted for clarity. N=8/group. B: Contralateral hindpaw. None of the menthol concentration groups were significantly different from the vehicles (0.01% menthol omitted). C: Vehicle controls: ipsilateral hindpaw. There was no significant difference between 10% + 1% Tween-80 and 50% ethanol + 5% Tween-80 vehicle groups. D: Vehicle controls: contralateral hindpaw. No significant difference between ethanol concentrations.