Search results
Results from the WOW.Com Content Network
Calcium signaling is the use of calcium ions (Ca 2+) to communicate and drive intracellular processes often as a step in signal transduction. Ca 2+ is important for cellular signalling , for once it enters the cytosol of the cytoplasm it exerts allosteric regulatory effects on many enzymes and proteins .
In any muscle cell, increased intracellular calcium causes contraction. In smooth muscle cells the elevated levels of intracellular calcium cause the opening of BK channels which in turn allow potassium ions to flow out of the cell. This causes further hyperpolarization and closing of voltage gated calcium channels, relaxation can then occur.
The US Institute of Medicine (IOM) established Recommended Dietary Allowances (RDAs) for calcium in 1997 and updated those values in 2011. [6] See table. The European Food Safety Authority (EFSA) uses the term Population Reference Intake (PRIs) instead of RDAs and sets slightly different numbers: ages 4–10 800 mg, ages 11–17 1150 mg, ages 18–24 1000 mg, and >25 years 950 mg. [10]
A calcium channel is an ion channel which shows selective permeability to calcium ions. It is sometimes synonymous with voltage-gated calcium channel, [1] which are a type of calcium channel regulated by changes in membrane potential. Some calcium channels are regulated by the binding of a ligand.
The concentration of calcium (Ca 2+ ions) is normally several thousand times higher outside the cell than inside. Activation of particular VGCCs allows a Ca 2+ influx into the cell, which, depending on the cell type, results in activation of calcium-sensitive potassium channels , muscular contraction , [ 4 ] excitation of neurons, up-regulation ...
Calcium regulation in the human body. [6]The plasma ionized calcium concentration is regulated within narrow limits (1.3–1.5 mmol/L). This is achieved by both the parafollicular cells of the thyroid gland, and the parathyroid glands constantly sensing (i.e. measuring) the concentration of calcium ions in the blood flowing through them.
An L-type calcium channel with its subunits labeled along with some drugs known to inhibit the channel. The L-type calcium channel (also known as the dihydropyridine channel, or DHP channel) is part of the high-voltage activated family of voltage-dependent calcium channel. [2] "L" stands for long-lasting referring to the length of activation.
The α 1 subunit of T-type calcium channels is similar in structure to the α subunits of K + (potassium ion) channels, Na + (sodium ion) channels, and other Ca 2+ (calcium ion) channels. The α 1 subunit is composed of four domains (I-IV), with each domain containing 6 transmembrane segments (S1-S6). The hydrophobic loops between the S5 and S6 ...