Figure 6. Single Ca²⁺ release channel currents through RyR1_N and RyR1_MHS and the effect of DP4.

Single Ca²⁺ channel currents through RyR1_N and RyR1_MHS were recorded at a holding potential of −40 mV (cis) in a symmetrical solution containing 250 mM caesium methanesulfonate buffered with 20 mM Hepes/Tris, pH 6.8, at 30 μM Ca²⁺. (A) Representative traces of the current recordings through RyR1_N (left-hand panels) and RyR1_MHS (right-hand panels) channels in the presence and absence of DP4 (upper six panels) or DP4-mut (lower four panels). The conductance level of the closed channel is shown by a short line on the side of each current recording. (B) Summary of the P_o data collected in the presence of 0–30 μM DP4 or 50 μM DP4-mut. Results are means±S.E.M. (n=3–10).