IP<sub>3</sub>-mediated Ca<sup>2+</sup> release regulates atrial Ca<sup>2+</sup> transients and pacemaker function by stimulation of adenylyl cyclases
Rebecca A. Capel, Samuel J. Bose, Thomas P. Collins, Skanda Rajasundaram, Thamali Ayagama, Manuela Zaccolo, Rebecca A.B. Burton, Derek A. Terrar
Abstract
This study provides evidence supporting the proposal that IP 3 signaling in cardiac atria and sinoatrial node involves stimulation of Ca 2+ -activated adenylyl cyclases (AC1 and AC8) by IP 3 -evoked Ca 2+ release from junctional sarcoplasmic reticulum. AC8 and IP 3 receptors are shown to be located close together, while AC1 is nearby. Greater understanding of these novel aspects of the IP 3 signal transduction mechanism is important for future study in atrial physiology and pathophysiology, particularly atrial fibrillation.
Topics & Concepts
Adenylyl cyclaseSinoatrial nodeStimulationEndoplasmic reticulumSignal transductionInternal medicineAtrial fibrillationReceptorChemistryEndocrinologyCell biologyBiologyMedicineHeart rateBlood pressureCardiac electrophysiology and arrhythmiasIon channel regulation and functionReceptor Mechanisms and Signaling