Figure 4

Typical force trace and the effect of incremental concentrations of levosimendan on submaximal force. (A) Typical force trace of a human cardiomyocyte. Force increases while exposing the cardiomyocyte to an experimental solution with submaximal exogenous calcium levels (pCa 6.5). Relaxation is induced by exposing the cardiomyocyte to an experimental solution with a very low calcium concentration (pCa 9.0). (B) The effect of incremental concentrations of levosimendan on submaximal force (approximately 40% of maximal force) of human cardiomyocytes. Prior to and directly after exposure to the levosimendan concentrations, cardiomyocytes were exposed to vehicle to rule out confounding effects of force rundown during the protocol. Note that at various concentrations (1, 25, and 100 μM) levosimendan significantly increased submaximal force. *P < 0.05.