title: Calcium movements inside the sarcoplasmic reticulum of cardiac myocytes.
abstract: Sarcoplasmic reticulum (SR) Ca content ([Ca]SRT) is critical to both normal cardiac function and electrophysiology, and changes associated with pathology contribute to systolic and diastolic dysfunction and arrhythmias. The intra-SR free [Ca] ([Ca]SR) dictates the [Ca]SRT, the driving force for Ca release and regulates release channel gating. We discuss measurement of [Ca]SR and [Ca]SRT, how [Ca]SR regulates activation and termination of release, and how Ca diffuses within the SR and influences SR Ca release during excitation-contraction coupling, Ca sparks and Cac waves. The entire SR network is connected and its lumen is also continuous with the nuclear envelope. Rapid Ca diffusion within the SR could stabilize and balance local [Ca]SR within the myocyte, but restrictions to diffusion can create spatial inhomogeneities. Experimental measurements and mathematical models of [Ca]SR to date have greatly enriched our understanding of these [Ca]SR dynamics, but controversies exist and may stimulate new measurements and analysis.
authors: Department of Pharmacology, University of California, Davis, Davis, CA, USA. dmbers@ucdavis.edu
authors: Donald M
authors: DM
authors: Bers
authors: Thomas R
authors: TR
authors: Shannon
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000378:metabolism* / Q000503:physiopathology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology; D006352:Heart Ventricles / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D009685:Nuclear Envelope / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism* / Q000502:physiology
chemical_list: D002118:Calcium