Figure 4. Radiocaine autoradiography with explanted human heart tissue.

(a) Summary of investigated subjects; NF = non-failing, F = failing (idiopathic dilated cardiomyopathy, DCM). (b) Comparison of specific radiocaine signal relative to group NF1 determined by autoradiography at equilibrium conditions with 500 μM lidocaine as blocking agent (N = 5, n ≥ 2, significance * is defined by p < 0.05 as determined by student t-test, error bars represent ± 1 stdev). (c) Dose-response experiments with increasing concentrations of fluorolidocaine. Using self-displacement, the IC₅₀-value generated with this assay equals the K_d-value. (N = 5, n = 1, error bars represent ± 1 stdev).