Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

The presence of numerous gap junctions between endocardial endothelial cells, but not between myocardial capillary endothelial cells, led to the investigation of cell-to-cell communication in cultured endocardial endothelium of the porcine right ventricle. Single cells, cell pairs and cell clusters were whole-cell voltage-clamped and simultaneously loaded from the pipette with combinations of fluorescent tracers of similar molecular weight but different charge. While capacitive and ionic currents were measured, emitted light intensity of the excited dyes during diffusion from the pipette was detected with a microscope photometer. The amount of dye in the cell (cluster) followed an exponential course with time constant (mean ± SEM) of 459 ± 120 s for cascade blue (MW: 645, charge: -3; 20 microM, n = 14), 352 ± 76 s for calcein, (MW: 623, charge: -6/+2; 5 microM, n = 13) and 1062 ± 218 s for sulforhodamine (MW: 607, charge: +/-; 20 microM, n = 18). The amplitude correlated with the electric capacity, ranging from 49 pF (single cell) to 1400 pF (large cell cluster). Extensive dye and electrical coupling between endocardial endothelial cells indicates rapid intercellular signalling, which might suggest more global modulation of cardiac performance by endocardial than by myocardial capillary endothelium.

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Presentation Number SAfransen0434
Keywords: endocardium, endothelium, dye-coupling, cell-capacity, gap-junction