Do calcium waves propagate between cells and synchronize alternating calcium release in rat ventricular myocytes?

Area of Science:

• Cell Biology
• Biophysics
• Physiology

Background:

• Cellular communication relies on signaling molecules like calcium ions (Ca2+).
• Intercellular Ca2+ waves are crucial for coordinating cellular activities.
• Understanding Ca2+ wave propagation is key to comprehending cell-to-cell signaling.

Purpose of the Study:

• To investigate Ca2+ wave propagation between electrically coupled cells.
• To determine if intercellular Ca2+ waves synchronize Ca2+ alternans.
• To explore the structural basis for differences in Ca2+ wave propagation.

Main Methods:

• Experiments on electrically coupled cell pairs.
• Induction of spontaneous Ca2+ waves by elevated external Ca2+.
• Confocal microscopy to analyze cell junctions and Ca2+ dynamics.

Main Results:

• Ca2+ wave propagation varied significantly with cell pair orientation (side-to-side vs. end-to-end).
• Side-to-side contacts facilitated Ca2+ release propagation, unlike end-to-end contacts.
• A 2.3 μm gap at intercalated discs in end-to-end contacts likely impedes Ca2+ wave propagation.
• No evidence found that intercellular Ca2+ wave propagation synchronizes Ca2+ alternans.

Conclusions:

• Cell-to-cell Ca2+ wave propagation is orientation-dependent, influenced by junctional structures.
• Intercellular Ca2+ wave propagation does not contribute to the synchronization of Ca2+ alternans.
• Structural features at cell-cell junctions significantly impact Ca2+ signal transmission.