Mechanical Alloknesis Test

Our behavioral test followed a previous study (Feng et al., 2018). Briefly, mice were fully acclimated by being placed in the test chamber 1 h quaque die (QD) for 3 consecutive days before each behavioral assay. The fur on the nape of the neck was shaved without any skin lesions. Von Frey filaments ranging from 0.008 to 1.0 g were used to deliver mechanical stimuli. The filaments touched the skin and held on for up to 1 s unless the mice scratched the shaved skin with their hindpaw. Five stimuli were delivered for each filament with a 10-s interval between adjacent two weights. The total response number to each filament was counted to evaluate the degree of mechanical itch.