Stimulus-secretion coupling in excitable cells: a central role for calcium.
Secretion of vesicular contents by exocytosis is a common feature of neuroendocrine secretory cells such as adrenal chromaffin cells and PC12 cells. Although it is clear that in these cells an elevation in intracellular calcium concentration, [Ca2+]i, is the triggering event that induces secretion, recent studies using video-imaging, patch-clamp and flash photolysis techniques have all indicated that the Ca2+ signal that triggers secretion is in fact very complex, with the subcellular distribution of Ca2+ being of particular importance along with the magnitude of the rise. It has become evident that Ca2+ signals with different spatial profiles can be triggered in the same cell by a given stimulus, depending upon the nature of the Ca2+ signalling pathway activated, and that this ability to be able to vary the method of delivery of Ca2+ into the cell is important physiologically, because it provides a means of obtaining differential activation of Ca(2+)-dependent processes.
Cheek
T R
TR
AFRC Laboratory of Molecular Signalling, Department of Zoology, Cambridge, UK.
Barry
V A
VA
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002417:Cattle; D002838:Chromaffin System / Q000378:metabolism*; D005089:Exocytosis / Q000502:physiology; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D010673:Pheochromocytoma / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction / Q000502:physiology; D014407:Tumor Cells, Cultured
D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium