Regional Differences in Ca2+ Signaling and Transverse-Tubules across Left Atrium from Adult Sheep

Figures

• 

  Figure 1. Ca2+ transient heterogeneity in left atria from sheep. Top panel shows representative Ca2+ transient (CaTr) recorded at 0.5 Hz in adult sheep cardiac myocytes isolated from the epicardium (EPI) and endocardium (ENDO) regions of the left appendage (blue and orange traces, respectively); the free wall region (FW) and the pulmonary vein (PV) region of the left atrium (green and red traces, respectively). Lower panel is Mean ± SEM diastolic Ca2+, CaTr amplitude, time to peak and time to 50% transient decay recorded in those four atrial regions. n = 21, 28, 37 and 35 cells for EPI, EnNDO, FW and PV groups, respectively. Data are represented as mean ± SEM with ** p < 0.01, *** p < 0.001, **** p < 0.0001 compared to EPI and # p < 0.05, ## p < 0.01 compared to ENDO.

• 

  Figure 2. T-tubule characteristics in left atria from sheep. Top panel shows representative images of atrial myocytes stained with di-8 ANNEPS and visualized under confocal microscopy from four regions, epicardium (EPI), endocardium (ENDO), free wall (FW) and pulmonary vein (PV). Images of ×2.8 magnification are shown (below). Lower panel is percentage of cells showing an organized t-tubule (TT) network (black bars) and no organized TT (grey bars), Mean ± SEM TT regularity in cells with organized TT network and associated TT density in each group of cells. Data for TT organization and regularity analysis are from EPI = 81; ENDO = 79; FW = 59 and PV = 76. Data for TT density analysis are from EPI = 48; ENDO = 63; FW = 43 and PV = 65. **** p < 0.0001 compare to EPI and ### p < 0.001, #### p < 0.0001 compare to ENDO.

• 

  Figure 3. Langendorff left atrial preparation. Perfusion through the circumflex artery after suture of the leaky branches was performed to be able to dissociate atrial cardiac myocytes from epicardium (EPI), endocardium (ENDO), Free Wall (FW) and pulmonary vein (PV) regions.