Figure 2

The effect of incremental concentrations of levosimendan on submaximal force (approximately 40% of maximal force) of NEB-NM slow-twitch (A) and mixed (B) muscle fibers. Prior to and directly after exposure to the levosimendan concentrations, fibers were exposed to vehicle to rule out confounding effects of force rundown during the protocol. Note that levosimendan did not increase force compared to vehicle. Similar results were observed in slow-twitch (C) and fast-twitch (D) muscle fibers of control subjects. NEB-NM, nemaline myopathy patients with mutations in the nebulin gene; CTRL, control.