Vanilloid antagonists inhibit the capsaicin-induced⁴⁵Ca uptake in MC/9 cells. Cells were challenged with 3 μmol/L capsaicin in the presence of increasing concentrations of capsazepine (○) or ruthenium red (▪). Points represent mean values from sets of five determinations in a single experiment; error bars indicate SEM. Two additional experiments in each case yielded similar results. The theoretical curves were calculated by fitting the measured values to the Hill equation.