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. Author manuscript; available in PMC: 2021 Nov 3.
Published in final edited form as: J Physiol. 2020 Oct 6;598(24):5639–5659. doi: 10.1113/JP279909

Figure 7. TRPV1 agonists constrict skeletal muscle arterioles.

Figure 7.

A and B, capsaicin (1 μm) constricts isolated, pressurized (60 mmHg) skeletal muscle arteries from wild-type but not TRPV1-null mice (WT, n = 5; TRPV1-null, n = 4; unpaired t test, ***P < 0.001). C, capsaicin constricts intact and endothelium-denuded gracilis arteries from rats with similar potency (n = 6). D and E, intravital imaging shows that capsaicin constricts radial branch arteries (red arrowheads) without affecting veins (green arrowheads). The insets (continuous yellow boxes) show expanded views of the designated area (dashed yellow boxes). Arteries from TRPV1-null mice are unresponsive to capsaicin and blue-light constricts arteries from TRPV1-Cre:ChR2 mice (WT, n = 7; KO, n = 5; TRPV1-ChR2, n = 5 arteries obtained from 3 (KO and TRPV1-ChR2) and 5 (WT) mice, one-way ANOVA, ***P < 0.001). F, in vivo arteriole diameter following treatment with nifidepine (3 μm, n = 5), capsaicin (1 μm, n = 3), and nifedipine–capsaicin (n = 3, from three mice, unpaired t test, *P = 0.027). G, proposed model for Ca2+-entry pathways underlying capsaicin-induced vasoconstriction.