Fig. 2.

Capsaicin sensitivity in TG neurons of C57BL/6 and BALB/c. A: images are representative bright-field and phase contrast images of TG cells from C57BL/6 and fluorescent IB₄ labeling. Scale bars indicate = 100 μm. B: cell size distributions of IB₄-positive [IB₄(+), shaded bars] and IB₄-negative [IB₄(−), white bars] neurons of C57BL/6 and BALB/c. C: image depicts a representative capsaicin-induced current in a TG neuron of C57BL/6. The concentration of capsaicin was 1 μM. D: capsaicin sensitivity in IB₄(+) and IB₄(−) neurons in C57BL/6 (n = 17/45 and 15/40, respectively) and BALB/c (n = 2/41 and 17/49, respectively). **P < 0.01 and ⁺⁺P < 0.01, between strains and IB₄-binding properties in the same strain, respectively, using Fisher's exact test. E: mean densities of capsaicin-induced currents in IB₄(+) and IB₄(−) neurons in C57BL/6 (n = 17 and 15, respectively) and BALB/c (n = 2 and 17, respectively). Statistical comparison between IB₄(+) neurons was not performed because the cell number for BALB/c was only 2.