FIGURE 7.

Co-expression with Sur1 changes the sensitivity of Trpm4 to Mg²⁺. A, single channel recordings of inside-out patches from COS-7 cells expressing Ci-Myc-Trpm4 alone or co-expressing FLAG-Sur1-Ce and Ci-Myc-Trpm4, as indicated. Patches were exposed first to Na₂-ATP (100 μm), then to Mg²⁺-ATP (100 μm), and then to 0 ATP. All solutions contained Ca²⁺ (1 μm). B, bar graph showing the mean (±S.E.) open channel probability (nPo) relative to that in Na₂-ATP for the three conditions in A, as indicated. Conditions were as follows: charge carrier, Cs⁺; 10 patches per condition. Sur1:Trpm4 plasmid ratio, 12:1; *, p < 0.05; **, p < 0.01.