Involvement of Ca2+ waves in excitation-contraction coupling of rat atrial cardiomyocytes

Optical Bioimaging: From Living Tissue to a Single Molecule: Atrio-Ventricular Difference in Myocardial Excitation-Contraction Coupling — Sequential Versus Simultaneous Activation of SR Ca2+ Release Units —

“…2C). When the properties of Ca 2+ sparks were compared, no difference was observed in the distribution and kinetics between the sub-sarcolemmal and center regions of atrial myocytes as well as between atrial and ventricular myocytes (3,11). Thus, the properties of Ca 2+ release units appear to be baisically the same between peripheral and central regions of the atrial myocyte and also between atrial and ventricular myocytes.…”

“…In ventricular cardiomyocytes loaded with the Ca 2+ sensitive fluoroprobe fluo-3, nonuniformity in Ca 2+ fluorescence with a "striped" appearance is observed during the initial phase of the Ca 2+ transient evoked by field stimulation (3). Points at which rise in Ca 2+ began several ms earlier than other regions are spaced at regular intervals of about 1.8 m m along the longitudinal axis of the cell (Fig.…”

“…The Ca 2+ release in atrial cardiomyocytes on depolarization propagates towards the cell central region with a velocity of about 100 mm / s and are inhibited by ryanodine (3,19). Activation of individual release sites occuring at the Z-line level has been visualized both in the subsarcolemmal and central region of the atrial cardiomyocyte (19).…”

“…In addition, cells were stained with the membrane-selective probe di-2-ANEPEQ after line scan analysis of Ca 2+ transients (Fig. 1B) (3,5). In addition to the heavily stained sarcolemma, transverse lines of di-2-ANEPEQ staining were observed at 1.8-m m intervals in the longitudinal direction, indicating the presence of T-tubular invaginations throughout the cell (Fig.…”

Enhancement of Ca2+Current Does Not Regulate the Speed of Depolarization-induced Ca2+Propagation Wave in Rat Atrial Myocytes

“…The mode of gating and the contribution of this set of RyRs to atrial functions remain uncertain. Confocal Ca 2+ imaging in field-stimulated and currentclamped atrial cells suggests that Ca 2+ release initiated at the periphery propagates into the interior of the myocytes (Berlin, 1995;Lipp et al, 1996;Hüser et al, 1996;Mackenzie et al, 2001;Kockskämper et al, 2001;Tanaka et al, 2001;. Confocal imaging in voltage-clamped atrial myocytes has demonstrated that the amount of central Ca 2+ release is dependent on the magnitude of Ca 2+ influx through the Ca 2+ channels (Woo et al, 2002; as well as on Ca 2+ diffusion (Woo et al, 2002).…”