Figure 1.

Sanshool activates D-hair neurons. A, Classification of cultured sensory neurons based on chemical sensitivity (n = 1187). B, Examples of calcium responses to chemical stimuli and staining with neurofilament 200 antibody in cultured sensory neurons. A presumptive D-hair (arrowhead) and nociceptor (arrow) are indicated. Seventy-four percent of sanshool-sensitive and GABA-sensitive but capsaicin-insensitive neurons stained for NF200 (n = 23) compared with 49% of all neurons tested (n = 669; p < 0.05, Fisher's exact test). C, The proportion of sanshool-sensitive and GABA-sensitive (San+, GABA+) but capsaicin-insensitive (Cap−) sensory neurons in cultures with or without NT4, a growth factor that promotes D-hair development. n = 1187 and 1293, in the absence and presence of NT4, respectively, from three independent cultures. **p < 0.01, two-proportion z test. D, Example of a D-hair fiber response to sustained (suprathreshold) mechanical force and subsequently exposed to 200 μm hydroxy-α-sanshool and percentage of responsive fibers. E, Maximal response of D-hair fibers to sanshool (San) and sustained mechanical stimuli (Mech). AP, Action potentials; Veh, vehicle. F, Example of an AM fiber response to sustained (suprathreshold) mechanical force and subsequently exposed to 200 μm hydroxy-α-sanshool and percentage of responsive fibers.