FIG. 4.
Ca2+ homeostasis in Anxa7−/− embryonic cardiomyocytes is intact. (A) Embryonic Anxa7−/− cardiomyocytes displayed spontaneous contractile activity accompanied by Ca2+ transients. Between the Ca2+ transients, stable diastolic Ca2+ levels were observed. Changes in Ca2+ are displayed as 340/380 nm. (B) Spontaneously beating Anxa7−/− embryonic cardiomoycytes responded to depolarization of the membrane potential by elevating the extracellular K+ concentration with an increase of Ca2+. (C) Extracellular perfusion with the RyR agonist caffeine evoked a transient Ca2+ increase in an embryonic Anxa7−/− cardiomyocyte. When the increase of the caffeine-induced Ca2+ transient was measured in WT and Anxa7−/− cardiomyocytes, no significant difference was noted.