A, Intravital imaging show that BCTC (1 μM) dilates in vivo radial branch arterioles (red arrows) without affecting arterioles in TRPV1- null mice or veins (green arrows). B, Mean arteriole dilation evoked by BCTC in WT and TRPV1-null mice (n = 5 mice, 5 arteries) and maximal dilation with zero Ca2+/EGTA (unpaired t-test). C and D, Concentration-dependent dilation by BCTC normalized to zero Ca2+/EGTA (n = 4 arteries, 4 mice, one-way ANOVA Tukey’s Multi. comp.). E BCTC-evoked dilation in small (~25 μm, n = 8 arteries, 5 mice) and medium (~60 μm, n = 5 arteries, 4 mice) diameter arteries (unpaired t-test). F, Resting tone in small (n = 5 arteries, 4 mice) and medium (n = 4 arteries, 4 mice) diameter arteries (unpaired t-test).