Figure 4  Mg2+-evoked currents in Xenopus oocytes expressing hMagT1 RNA transcripts. Current was continuously monitored in a single oocyte expressing hMagT1 clamped at -100 mV and superfused for the period indicated, first with modified Barth’s solution containing 0 mM magnesium then with 2.0 mM magnesium and finally returning to magnesium-free solution.