Beat-to-Beat Variation in Periodicity of Local Calcium Releases Contributes to Intrinsic Variations of Spontaneous Cycle Length in Isolated Single Sinoatrial Node Cells.

ABSTRACT:

Unlabelled

Spontaneous, submembrane local Ca(2+) releases (LCRs) generated by the sarcoplasmic reticulum in sinoatrial nodal cells, the cells of the primary cardiac pacemaker, activate inward Na(+)/Ca(2+)-exchange current to accelerate the diastolic depolarization rate, and therefore to impact on cycle length. Since LCRs are generated by Ca(2+) release channel (i.e. ryanodine receptor) openings, they exhibit a degree of stochastic behavior, manifested as notable cycle-to-cycle variations in the time of their occurrence.

Aim

The present study tested whether variation in LCR periodicity contributes to intrinsic (beat-to-beat) cycle length variability in single sinoatrial nodal cells.

Methods

We imaged single rabbit sinoatrial nodal cells using a 2D-camera to capture LCR

SUBMITTER: Monfredi O 

PROVIDER: S-EPMC3695077 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature