Fig. 3.

Co²⁺ histochemistry on the 3T3 cell line expressing TRPV1 ectopically. Cells were incubated for 10 min in buffer A containing a 20 μM CAPS + 5 mM Co²⁺; b 20 μM CAPS + 5 mM Co²⁺ + 5 μM CapZ; c 5 mM Co²⁺ without CAPS. The dark CoS precipitate indicates the presence of intracellular Co²⁺ that is blockable with CapZ, a competitive antagonist of pungent vanilloids. d Gray values of the 3T3 cell line expressing TRPV1 measured by means of ImageJ software. e Co²⁺ histochemistry in CAPS-sensitive rat DRG neurons. Scale bar = 0.05 mm. These results confirm that Co²⁺ not only acts as a blocker but also enters the cell with Ca²⁺ through the TRPV1 channel