Fig. 7

Concentration–response curves for KB-R7943 (A), Ni²⁺ (B), SEA0400 (C) and imipramine (D) at 25°C (black) or 35°C (red). In A–D, each symbol represents mean ± SEM from 3–8 cells. At 20 µM KB-R7943 and 35°C in A, the initial Δ[Mg²⁺]_i/Δt values were similar in the three cells that were continuously illuminated by UV light throughout the run (column b of Fig. 5E) and the other three cells that were intermittently illuminated (column c of Fig. 5E). We therefore treated data from all 6 cells as a single group for the statistical analysis. Similarly, at 30 µM KB-R7943 and 35°C in A, we calculated statistical values from three cells; two with intermittent illumination and the other with continuous illumination. In A, B, and D the solid lines indicate the least-squares fit of the data set by the Hill-type curve with the values shown in the panel: \( {\text{Relative}}\,\Updelta [{\text{Mg}}^{2 + } ]_{\text{i}} /\Updelta t = { \max }\left( {1 - {\frac{{\left[ X \right]^{N} }}{{K_{\text{i}}^{N} \, + \, \left[ X \right]^{N} }}}} \right), \) where max is relative Δ[Mg²⁺]_i/Δt in the absence of the inhibitor X, N is the Hill coefficient, and K _i is IC₅₀. *0.01 ≤ P < 0.05; **P < 0.01 versus relative Δ[Mg²⁺]_i/Δt in the absence of the inhibitor