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 Ca2+ 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 [Ca2+] 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 Ca2+ influx and do not involve release from intracellular stores. The possible physiological implications of this new pathway of intracellular signalling are discussed.
- Action-potential clamp
- Calcium oscillations
- Indo-1 microspectrofluorometry
- Ionic channels
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Cell Biology