Figure 5. TRPV1 functionality in arterial smooth muscle cells.

A–D, Ca²⁺ transients evoked by capsaicin (1 μm) and KCl (50 mm) in isolated cerebellar arteries from wild-type and TRPV1-null mice (n = 40–70 cells in the groups from three independent experiments, unpaired t test, ***P < 0.001; **P = 0.0079 and ns, P = 0.15). E and F, Capsaicin-evoked Ca²⁺ signalling in dissociated ASM cells from TRPV1-Cre:tdTomato mice is restricted to TRPV1⁺ cells (31/38 TRPV1⁺ and 0/31 TRPV1^−/− cells). G, capsaicin- and K⁺-evoked responses require extracellular Ca²⁺ (0 mm Ca²⁺, n = 20, 1.2 mm Ca²⁺, n = 30; unpaired t test, **P < 0.01. H, representative current traces in a voltage-clamped (−50 mv) ASM cell (10 pF) in response to capsaicin (filled bars, 5 μm) with or without the TRPV1 antagonist BCTC (open bars, 5 μM), and recovery after washout. I, mean current density in ASM cells in response to capsaicin (n = 9) and capsaicin + BCTC (n = 3, unpaired t test, **P = 0.0013) and in nodose ganglion neurons (n = 7).