Propagation of a calcium pulse between osteoblastic cells

Area of Science:

• Cell Biology
• Biophysics
• Calcium Signaling

Background:

• Cell-to-cell communication is crucial in multicellular organisms.
• Calcium ions (Ca2+) play a vital role in various cellular processes, including signaling.
• Understanding the mechanisms of intercellular calcium propagation is essential for comprehending tissue function.

Purpose of the Study:

• To investigate the propagation of intracellular calcium concentration changes between bone cells following mechanical perturbation.
• To elucidate the role of extracellular calcium and gap junctions in this signaling process.
• To explore the underlying mechanism of calcium pulse propagation.

Main Methods:

• Utilized rat calvaria cells and osteosarcoma cells in primary culture.
• Employed laser scanning confocal microscopy and the fluorescent indicator fluo-3/AM.
• Manipulated extracellular calcium levels and used halothane to block gap junctions.

Main Results:

• Mechanical perturbation induced a transient intracellular calcium increase (pulse) in individual cells.
• This calcium pulse propagated from cell to cell, even through thin cellular processes.
• Propagation was dependent on extracellular calcium and inhibited by halothane, indicating gap junction involvement.
• Propagation velocity remained consistent between successive cell-to-cell transfers.

Conclusions:

• Mechanical stress initiates a propagating intercellular calcium signal in bone cells.
• Gap junctions and extracellular calcium are critical for this signaling.
• The findings suggest a self-regenerating calcium signaling mechanism, potentially involving calcium-induced calcium release.