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

    loading  Checking for direct PDF access through Ovid

Abstract

The aim was to investigate the propagation of Ca2+ waves between cells and determine whether this synchronizes alternating Ca2+ release between cells. Experiments were carried out on electrically coupled cell pairs; spontaneous Ca2+ waves were produced by elevating external Ca2+. There was a significant difference in the ability of these waves to propagate between cells depending on the orientation of the pairs. Although almost all pairs connected by side-to-side contacts showed propagating Ca2+ release, this was very uncommon in end-to-end cell pairs. Confocal studies showed that there was a gap at the intercalated disc consisting of cell membranes and a region of cytoplasm devoid of sarcoplasmic reticulum. This gap was 2.3 μm in length and is suggested to interfere with Ca2+ wave propagation. The gap measured was much smaller between side-to-side contacts: 1.5 μm and so much less likely to interfere with propagation. Subsequent experiments investigated the synchronization between cells of Ca2+ alternans produced by small depolarizing pulses. Although this alternation results from beat-to-beat alternation of intracellular Ca2+ wave propagation, there was no evidence that propagation of Ca2+ waves between cells contributed to synchronization of this alternans.

Related Topics

    loading  Loading Related Articles