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. 2005 Sep 28;25(39):8924–8937. doi: 10.1523/JNEUROSCI.2574-05.2005

Figure 3.

Figure 3.

Camphor induces [Ca2+]i rise in TRPV1- and TRPV3-expressing cells but not in TRPV2-expressing cells. A, Camphor and capsaicin increased fura-2 ratios (F340/F380) of HEK cells transfected with the rTRPV1-EGFP construct. EGFP-positive cells were identified by measuring F440. TRPV1-positive cells had higher fura-2 ratios under resting states, indicative of higher basal [Ca2+]i level. Camphor (5 mm) increased fura-2 ratios in most of these TRPV1-positive (expressing) cells with no, or only very minimal, effects on TRPV1-negative cells. Capsaicin (1 μm) induced increases of fura-2 ratios in almost all of the TRPV1-positive cells. All cells responded to Ca2+ ionophore ionomycin (1 μm). B, Average changes (mean ± SEM; solid line) in the fura-2 ratio induced by camphor and capsaicin in TRPV1-positive cells (blue) and TRPV1-negative cells (black). Responses from individual cells were plotted in dotted lines of various colors. C, D, Camphor (5 mm) failed to increase fura-2 ratios in TRPV2-positive cells. The same cells responded with 200–500 μm DPBA, an agonist of TRPV1–3 channels. E, F, TRPV3-expressing cells responded strongly to camphor (5 mm) but not to capsaicin (1 μm).