Figure 4. SERCA inhibitors do not affect the Ca²⁺ sensitivity of contractile proteins.

Measurements of the external diameter of β-escin-permeabilised arterioles. A and B, free ionised Ca²⁺ concentrations in the bath solution are given in μM. A, effect of GTP-γ-S (10 μM) in the presence of 0.1 μM Ca²⁺. B and C, for a paired experiment carried out on one day, the effects of increasing concentrations of Ca²⁺ on an arteriole in control conditions (B) and on another arteriole in the presence of 10 μM CPA (C). D and E, mean ± s.e.m. diameter of arterioles as a percentage of the initial diameter in the absence of Ca²⁺, shown for control and 10 μM CPA paired data (n = 11 for each), and control and 1 μM TG paired data (n = 6 for each).