Fig. 6.

ICL1–9 promotes β₂AR-mediated cardiomyocyte contraction, whereas carvedilol does not demonstrate similar efficacy. (A) WT adult murine cardiomyocytes were isolated and assessed for basal and agonist-promoted contractility using a digital videocamera-coupled microscope in the presence or absence of 0.1% DMSO, 0.5 μM isoproterenol, 10 μM carvedilol, 10 μM ICL1–9, or 10 μM control pepducin. Representative cell length (in micrometers) tracings at 2 Hz in the basal or stimulated state for each test condition are reported. (B) ICL1–9 was able to promote significant contraction in WT adult murine cardiomyocytes, whereas carvedilol did not stimulate a similar effect. The data are represented by the mean ± SEM from n = 4–8 individual cardiomyocytes from at least three independent primary isolations. ns, not significant, ***P < 0.001 using a one-way ANOVA with Newman–Keuls multiple comparison test.