Limited intercellular spread of spontaneous Ca2+ signals via gap junctions between mouse chromaffin cells in situ

Abstract Using a confocal laser-scanning microscope, we measured the changes in the cytosolic Ca 2+ concentration ([Ca] i ) of chromaffin cells on adrenal slice preparations of mouse. The spontaneous fluctuations of [Ca] i were often observed in situ, as reported in isolated rat and bovine cells. Intriguingly, the spontaneous [Ca] i changes in one cell were often transmitted to one or two adjacent cells, and the synchronized [Ca] i changes were often observed in two adjacent cells, both of which failed to respond to ATP. The synchronized [Ca] i changes between two cells were much less frequently observed in rat than in mouse adrenals. The spontaneous [Ca] i changes were also synchronized between closely touching mouse chromaffin cells in culture. These results suggest that the spread of Ca 2+ signaling is mediated by low-conductance intercellular coupling.