Unknown

Dataset Information

0

Beat-to-beat Ca(2+)-dependent regulation of sinoatrial nodal pacemaker cell rate and rhythm.


ABSTRACT: Whether intracellular Ca(2+) regulates sinoatrial node cell (SANC) action potential (AP) firing rate on a beat-to-beat basis is controversial. To directly test the hypothesis of beat-to-beat intracellular Ca(2+) regulation of the rate and rhythm of SANC we loaded single isolated SANC with a caged Ca(2+) buffer, NP-EGTA, and simultaneously recorded membrane potential and intracellular Ca(2+). Prior to introduction of the caged Ca(2+) buffer, spontaneous local Ca(2+) releases (LCRs) during diastolic depolarization were tightly coupled to rhythmic APs (r²=0.9). The buffer markedly prolonged the decay time (T??) and moderately reduced the amplitude of the AP-induced Ca(2+) transient and partially depleted the SR load, suppressed spontaneous diastolic LCRs and uncoupled them from AP generation, and caused AP firing to become markedly slower and dysrhythmic. When Ca(2+) was acutely released from the caged compound by flash photolysis, intracellular Ca(2+) dynamics were acutely restored and rhythmic APs resumed immediately at a normal rate. After a few rhythmic cycles, however, these effects of the flash waned as interference with Ca(2+) dynamics by the caged buffer was reestablished. Our results directly support the hypothesis that intracellular Ca(2+) regulates normal SANC automaticity on a beat-to-beat basis.

SUBMITTER: Yaniv Y 

PROVIDER: S-EPMC3208800 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

altmetric image

Publications

Beat-to-beat Ca(2+)-dependent regulation of sinoatrial nodal pacemaker cell rate and rhythm.

Yaniv Yael Y   Maltsev Victor A VA   Escobar Ariel L AL   Spurgeon Harold A HA   Ziman Bruce D BD   Stern Michael D MD   Lakatta Edward G EG  

Journal of molecular and cellular cardiology 20110914 6


Whether intracellular Ca(2+) regulates sinoatrial node cell (SANC) action potential (AP) firing rate on a beat-to-beat basis is controversial. To directly test the hypothesis of beat-to-beat intracellular Ca(2+) regulation of the rate and rhythm of SANC we loaded single isolated SANC with a caged Ca(2+) buffer, NP-EGTA, and simultaneously recorded membrane potential and intracellular Ca(2+). Prior to introduction of the caged Ca(2+) buffer, spontaneous local Ca(2+) releases (LCRs) during diastol  ...[more]

Similar Datasets

| S-EPMC3791306 | biostudies-literature
| S-EPMC2386925 | biostudies-literature
| S-EPMC5054686 | biostudies-literature
| S-EPMC3735682 | biostudies-literature
| S-EPMC6138244 | biostudies-literature
| S-EPMC5391769 | biostudies-literature
| S-EPMC4312254 | biostudies-literature
| S-EPMC7641277 | biostudies-literature
| S-EPMC3816448 | biostudies-literature
| S-EPMC2735135 | biostudies-literature