Figure 6

The distribution of neurons expressing TRPA1 channels in the TG and dural afferent neurons. (A) Representative images of a TG section containing a FG⁺/TRPA1⁺ dural afferent neuron (indicated by the arrowheads; scale bar: 20 μm). (B) The percentage of TRPA1⁺ TG neurons in the V₁/V₂ and V₃ divisions (n = 3 mice; on average, 576 V₁/V₂ neurons and 428 V₃ neurons were counted from each mouse). (C) The percentages of TRPA1⁺ V₁/V₂ TG neurons (the same data as in B) and FG⁺ dural afferent neurons (n = 3 mice, on average, 206 FG⁺ neurons were counted from each mouse). (D) The size distribution of TRPA1⁺/FG⁺ dural afferent neurons are significantly smaller than those of the TRPA1⁺ neurons in the V₁/V₂ divisions of the TG (n = 35 and 130 neurons pooled from three mice, respectively; p < 0.05, Mann–Whitney U test). (E) The sizes of TRPA1⁺ neurons (the same neurons as in D) are significantly smaller than those of the neurons in the V₁/V₂ divisions of the TG (n = 1729 neurons pooled from three mice, p < 0.001, Mann–Whitney U test). (F) The sizes of TRPA1⁺/FG⁺ dural afferents (the same neurons as in D) are significantly smaller than those of the total FG⁺ dural afferent neurons (n = 620 neurons pooled from three mice, p < 0.001, Mann–Whitney U test). (G) Nearest-neighbor measurement shows that both FG⁺ dural afferent neurons and TRPA1⁺ neurons are randomly distributed in the TG (n = 130 TRPA1⁺ neurons and 620 FG⁺ dural afferent neurons from 3 mice, the same cells as in D and F). (H) A modified nearest-neighbor measurement shows that TRPA1⁺ neurons are clustered around some, but not all, of the FG⁺ dural afferent neurons (the same neurons as in G).