Current records and simulations. (A) Ca²⁺ current through a bilayer-reconstituted coupled RyR2 pair from dog heart in the presence of [Ca²⁺]_cis ∼100 µM and [Ca²⁺]_trans ∼50 mM. (B) Ca²⁺ current through a coupled RyR2 pair from rat heart, classified as “low activity,” in the presence of [Ca²⁺]_cis = 170 µM and [Ca²⁺]_trans ∼50 mM. C₁ and C₂, model currents, assuming the array of three channels represented in Fig. 10 A, with ε_OO = −0.8 and ε_CC = ε_OC = ε_CO = 0 (C₁) or ε_CC = ε_OO = −0.8 (C₂). The shaded bars represent the probability of configurations with m channels open. Panels A and B reproduce panels from Figs. 1 and 2. Panels C₁ and C₂ are reproduced from Fig. 3 in Groff and Smith (2008) by courtesy of Greg Conradi Smith. Fig. 11 is reprinted with permission from Elsevier.