Related Experiment Video
Updated: Jun 15, 2026
12:10
Measuring Fast Calcium Fluxes in Cardiomyocytes
Published on: November 29, 2011
Local Ca2+ releases enable rapid heart rates in developing cardiomyocytes
Topi Korhonen1, Risto Rapila, Veli-Pekka Ronkainen
1University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, Department of Biotechnology and Molecular Medicine, PO Box 1627, FIN-70211 Kuopio, Finland. pasi.tavi@uef.fi
The Journal of Physiology
|March 10, 2010
Summary
Developing heart cells use local calcium releases to ensure rhythmic contractions. This mechanism, involving sarcoplasmic reticulum structures, is vital for heart function from early development through birth.
Area of Science:
- Cardiology
- Cell Biology
- Developmental Biology
Background:
- Mammalian cardiac myocyte contraction relies on high-frequency, homogeneous intracellular calcium (Ca2+) oscillations.
- Mechanisms for these Ca2+ signals in adult cardiomyocytes are known, but not in developing ones.
Purpose of the Study:
- Investigate mechanisms reducing spatial and temporal heterogeneity of cytosolic Ca2+ signals in mouse embryonic ventricular cardiomyocytes.
- Understand how developing cardiomyocytes generate homogeneous, high-frequency Ca2+ signals.
Main Methods:
- Experimental investigation of cytosolic Ca2+ signals in embryonic cardiomyocytes.
- Analysis of sarcoplasmic reticulum (SR) structures and their components (SERCA, RyRs).
- Mathematical modeling of Ca2+ signal propagation.
Main Results:
- Developing cardiomyocytes amplify propagating Ca2+ signals via local Ca2+ releases in the cytosol.
- Regular 3-D SR structures with SERCA and RyRs facilitate these local releases.
- Local releases increase cytosolic Ca2+ propagation speed threefold by evoking Ca2+-induced Ca2+ sparks.
- Mathematical modeling confirmed loss of homogeneous, high-frequency Ca2+ signaling without local release sites.
Conclusions:
- Local cytosolic Ca2+ releases are essential for developing cardiomyocytes to achieve homogeneous, high-frequency Ca2+ signaling.
- This mechanism is crucial for normal mammalian cardiomyocyte function from embryonic development to post-natal differentiation.
- The identified mechanism is indispensable for normal heart development and function.
More Related Videos
Related Concept Videos
01:27Specialized Characteristics of Cardiac Muscles
The primary role of cardiac muscles is to propel blood throughout the cardiovascular system. The cardiac muscle cells, or cardiomyocytes, exhibit specialized characteristics that allow them to perform this function.
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
01:31Regulation of Heart Rates
The regulation of heart rate is a complex process controlled by the autonomic nervous system (ANS), hormonal influences, and intrinsic cardiac mechanisms. The ANS has two main components: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).
The SNS increases heart rate through the release of norepinephrine and epinephrine, which act on beta-1 adrenergic receptors in the heart. This action increases the rate of depolarization in the sinoatrial (SA) node, the heart's...
The SNS increases heart rate through the release of norepinephrine and epinephrine, which act on beta-1 adrenergic receptors in the heart. This action increases the rate of depolarization in the sinoatrial (SA) node, the heart's...
01:19Electrophysiology of Normal Cardiac Rhythm
The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase of...
01:28Mechanism of Cardiac Arrhythmias
Arrhythmias are irregular heart rhythms occurring when the heart's electrical impulses become abnormal. These disturbances can lead to various symptoms, depending on their severity and the underlying cause. Some common factors contributing to arrhythmias include hypoxia, ischemia, electrolyte imbalances, excessive catecholamine exposure, drug toxicity, and muscle overstretching. Arrhythmias can be classified into two main types based on the rate and site of origin of abnormal heart rhythms.
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...