Figure 4. Effect of levosimendan on NCX activity in cultured human cardiomyocyte progenitor cell (hCPC)-derived cardiomyocytes after anoxia/reoxygenation (A/R).

(A) Reverse-mode NCX activity was measured with or without treatment of Levosimendan under control conditions (a), after anoxia for 2 hours (b), and after anoxia for 14 hours (c). Reverse-mode NCX activity 2 and 14 hours of anoxia were determined; higher expression of GRP78 and caspase 12 did not reach statistical significance until 14 hours of anoxia (Figure 7). (B) NCX activity was estimated by amplitude of increase in intracellular calcium concentration. (Δ[Ca²⁺]_i = peak [Ca²⁺]_i - basal [Ca²⁺]_i). (n = 15 for each experimental group). Values are expressed as mean ± S.D. from three independent trials. *p<0.05 versus untreated control; **p<0.01 versus untreated control and anoxia for 2 h. Similar results emerged from three independent experiments. A: anoxia; Ctrl: control; Re: reoxygenation; Levo: Levosimendan.