Temporal transition of Vegf receptor expression in teeth. (A–F) Immunohistochemistry of a mandible centered on the first molar. Vegfr1^high and Vegfr2^high ECs are actively sprouting (open arrowheads) and lack smooth muscle cells (closed arrowheads). ASMA, α-smooth muscle actin. (A–C) These images show separate channels of Fig. 1 I. (D)Fig. 1 D shows the same image for the sake of convenience. (G–U) Immunohistochemistry for mandibles centered on the first molar. Looping venules (arrows) were clearly detected after P6, while Vegfr1^highVegfr2^high POTCs (closed arrowheads) developed at ∼P12. (V) qPCR analysis of isolated CD31⁺ dental pulp cells (n = 4 respectively). Scale bars: 200 µm (G–K); 50 µm (D–F and L–U); 20 µm (A–C). Data are presented as means ± SD.