Figure 2

Nur77-KO cardiomyocytes exhibit altered [Ca²⁺]_i homeostasis.

Adult cardiomyocytes were isolated from at least 3 different WT and Nur77-KO mice. Baseline measurements were performed in WT (n = 31) and Nur77-KO (n = 33) cardiomyocytes, of which 14–19 per group were subsequently stimulated with isoproterenol (ISO) or norepinephrine (NOR). (a) Representative [Ca²⁺]_i transient and amplitude quantification. [Ca²⁺]_i transient amplitudes were significantly higher in Nur77-KO cardiomyocytes at baseline and upon stimulation with either isoproterenol or norepinephrine. (b) Amplitude increase relative to baseline upon adrenergic stimulation did not differ between WT and Nur77-KO cardiomyocytes. (c) Basal diastolic [Ca²⁺]_i concentration was significantly elevated in Nur77-KO cardiomyocytes, while transient peak and decay times were unchanged compared to WT cardiomyocytes. Data presented as mean±SEM; *p < 0.05, **p < 0.01.