A novel pattern of fast calcium oscillations points to calcium and electrical activity cross-talk in rat chromaffin cells.
Slow oscillations of cytosolic calcium ion concentration - [Ca(2+)](c) - typically originate from release by intracellular stores, but in some cell types can be triggered and sustained by Ca(2+) influx as well. In this study we simultaneously monitored changes in [Ca(2+)](c) and in the electrical activity of the cell membrane by combining indo-1 and patch-clamp measurements in single rat chromaffin cells. By this approach we observed a novel type of spontaneous [Ca(2+)](c) oscillations, much faster than those previously described in these cells. These oscillations are triggered and sustained by complex electrical activity (slow action potentials and spike bursts), require Ca(2+) influx and do not involve release from intracellular stores. The possible physiological implications of this new pathway of intracellular signalling are discussed.
Micheletti
M
M
S. Raffaele Scientific Institute, Milano, Italy.
Brioschi
A
A
Fesce
R
R
Grohovaz
F
F
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology; D020013:Calcium Signaling / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000737:chemistry / Q000502:physiology*; D005470:Fluorometry; D010539:Permeability; D051381:Rats
D015220:Calcium Channels; D002118:Calcium