Figure 5

The distribution of neurons expressing TRPV1 channels in the TG and dural afferent neuron populations. (A) Representative images of a TG section containing FG⁺ dural afferent neurons and neurons exhibiting TRPV1-ir. Arrowheads indicate neurons that are both FG⁺ and TRPV1⁺. (B) The percentage of TRPV1⁺ TG neurons in the V₁/V₂ and V₃ divisions (n = 3 mice; on average, 730 V₁/V₂ neurons and 500 V₃ neurons were counted from each mouse; *** p < 0.001, two-tailed t-test). (C) The percentages of V₁/V₂ TG neurons (the same data set as in B) and FG⁺ dural afferent neurons that are TRPV1⁺ (n = 3 mice, on average, 213 FG⁺ neurons were counted from each mouse; * p < 0.05, two-tailed t-test). (D) The size distribution of TRPV1⁺/FG⁺ dural afferent neurons (n = 151 neurons pooled from three mice) are similar to the TRPV1⁺ neurons in the V₁/V₂ divisions of the TG (n = 679 neurons pooled from three mice, p = 0.1, Mann–Whitney U test). (E) The sizes of TRPV1⁺ neurons (the same neurons as in D) are significantly smaller than those of the neurons in the V₁/V₂ divisions of the TG (n = 2189 neurons pooled from three mice, p < 0.001, Mann–Whitney U test). (F) The sizes of TRPV1⁺/FG⁺ dural afferents (the same neurons as in D) are significantly smaller than those of the total FG⁺ dural afferent neurons (n = 638 neurons pooled from three mice, p < 0.001, Mann–Whitney U test).