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

Using a confocal laser-scanning microscope, we measured the changes in the cytosolic Ca2+, 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 [Call 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 21 signaling is mediated by low-conductance intercellular coupling. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.