Fig. 2.

Records from six separate experiments in which Mg²⁺ efflux was induced by addition of 140 mM Na⁺, at the times indicated by the arrows, in the absence of the inhibitor (A) or in the presence of 30 µM KB-R7093 (B), 100 µM KB-R7943 (C), 10 µM SEA0400 (D), 200 µM imipramine (E), or 5 mM Ni²⁺ (F) at 25°C. In this figure and Fig. 5, [Mg²⁺]_i traces have been smoothed with adjacent averaging of 51 data points (10 s) to reduce noise of the graphic display. In each panel, a solid line was drawn by the least-squares fit to unsmoothed data points; the initial Δ[Mg²⁺]_i/Δt estimated from the slope is indicated (µM/s) near the trace