Figure 2. Concentration dependence of the effects of omecamtiv mecarbil (OM) and blebbistatin (BS) on isometric force development of native demembranated rat right ventricular trabeculae.

A and B, dose–response curves for OM and BS, respectively, on passive force at pCa 9 (filled circles), and active force at pCa 6 (grey circles) and pCa 4.3 (open circles). Isometric forces were normalized to that at pCa 4.3 in the absence of drugs (T ₀). Values indicate means ± SEM (n = 3). BS reduced passive force at pCa 9 (filled circles) by ∼60% with an EC₅₀ of 2.3 ± 0.9 μmol L⁻¹.