Fig. 2.

Effect of p38 MAPK inhibition with SB-203580 (SB) on changes in rat ventricular cardiomyocyte Ca²⁺ transient ratio magnitudes elicited by isoproterenol (ISO) and CCPA. β-Adrenoceptors were stimulated with 1 nM ISO for 3 min in the absence or presence of the A₁R agonist CCPA at 1.0 μM. Experiments were conducted in the absence (A) or presence (B) of the p38 MAPK inhibitor SB (1 μM). Representative calcium transients are depicted above the corresponding bars. Horizontal bar (s) indicates 1 s. Values are means ± SE for 7 (without SB) or 11 (with SB) cardiomyocytes. *Means are significantly different from the appropriate ISO-free control (P < 0.05). †Mean is significantly different from the ISO value in the absence of CCPA (P < 0.05).