The calcium in the blood is important for a number of functions, including blood clotting, transmission of nerve impulses, muscle contraction, stability of cell membranes, and cell metabolism. This mineral provides the structural integrity of the skeleton. Of these three, the free cation is the most important for the physiological functions described in the paragraph above, and its concentration must be carefully maintained.
For instance, muscle contraction is initiated by a sudden increase in calcium concentration in the muscle cells. The body has several mechanisms to maintain these ion concentrations. The cells have channels and pumps that regulate the flow of calcium ions between the cells and the extracellular fluids via the cell membrane. In addition, the calcium ions can be removed from or bound to the calcium-binding proteins in order to increase or decrease, respectively, the free-ion concentration. Why remdesivir does not fully stop the coronavirus January 13, Corona Structural Biology.
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Toggle navigation PDB Educational portal of. Molecule of the Month. Calcium Pump Atomic structures have captured the calcium pump in action Calcium pump, with two bound calcium ions in turquoise. The membrane is shown schematically in gray. Every time we move a muscle, it requires the combined action of trillions of myosin motors.
Our muscle cells use calcium ions to coordinate this massive molecular effort. When a muscle cell is given the signal to contract from its associated nerves, it releases a flood of calcium ions from a special intracellular container, the sarcoplasmic reticulum, that surrounds the bundles of actin and myosin filaments.
Scientists can also measure the number and location of channels inside the heart cell by attaching light-emitting indicators to the channels, which can be visualized under a microscope. More recently, scientists have started to use computer models to put all these data together, to help them predict the effect that changes in calcium regulation will have within heart cells [ 4 ].
The improved understanding of heart rhythm disorders has helped to predict which patients have a high risk of these problems and has also resulted in better therapies [ 5 ]. For example, drugs can be used to block the ion channels so that the doors stay closed and the amount of calcium inside the cell is controlled. Alternatively, specialized doctors can put a small device into the heart, through the blood vessels, to take out the heart cells that produce unwanted signals so that they no longer cause fibrillation Figure 3.
Despite the impressive advancements in bio medical technologies, numerous important questions about the mechanisms and treatment of calcium-related problems inside heart muscle cells remain. Several research groups across the world are working hard to answer these questions. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Ion channels in the heart. The multiple proarrhythmic roles of cardiac calcium-handling abnormalities: triggered activity, conduction abnormalities, beat-to-beat variability, and adverse remodelling. Arrhythmogenic mechanisms in heart failure: linking beta-adrenergic stimulation, stretch, and calcium. Investigational antiarrhythmic agents: promising drugs in early clinical development. Expert Opin. Share on Facebook. Core Concept Published: May 10, Abstract The heart is a pump that brings blood to every part of the body.
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