Fig. 3
C3 is a specific agonist of TRPM8. (a) Image shows fluorescence emission of Ca2+ influx in response to excitation by Fura2-AM loading. C3 (10 μM) activates neurons (green) from culturedTrpm8 EGFPf/+transgenic mice which are also menthol (100 μM) sensitive. White arrows indicate the responsive neurons. Scale bar: 100 μm. (b) Representative calcium traces for C3 and menthol on Trpm8 EGFPf/+ (Trpm8 +/−) orTrpm8 EGFPf/EGFPf (Trpm8 −/−) transgenic neurons. High concentration of K+ (KCl) was used to identify the total number of neurons. (c) Quantification of C3 and menthol activation on Trpm8 +/−(n = 104) andTrpm8 −/−transgenic neurons (n = 136). High concentration of K+ (KCl) was used to identify the total number of neurons. (d, e) C3 does not activate mouse TRPV1 or human TRPA1 ion channels in heterologous KNRK cells, which are activated by positive control substances, TRPV1 capsaicin (10 μM), or TRPA1 mustard oil (100 μM), respectively)