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Calcium channel blockers (CCB), calcium channel antagonists or calcium antagonists [2] are a group of medications that disrupt the movement of calcium (Ca 2+) through calcium channels. [3] Calcium channel blockers are used as antihypertensive drugs, i.e., as medications to decrease blood pressure in patients with hypertension.
Compared with certain other L-type calcium channel blockers (for example those of the phenylalkylamine class such as verapamil) that have significant action at the heart, the dihydropyridine calcium channel blockers lower blood pressure mainly by relaxing the smooth muscle of the blood vessel walls. [3]
Antihypertensives are classified by different mechanisms or sites of action. Some of the most commonly used drugs to treat hypertension include diuretics, angiotensin-converting enzyme inhibitors (ACEI), angiotensin II receptor blockers (ARBs), calcium channel blockers (CCBs), and beta-blockers.
When extracellular calcium flows into N-type calcium channels due to an action potential, it triggers the fusion of the secretory vesicles. Studies on the cardiovascular system reveal when ω-Conotoxin is introduced, it causes the inhibition of norepinephrine , and this shows that only the N-type calcium channel, not the P/Q/L type calcium ...
Conversely, when open channel blockers bind to the cell they prevent the normal function of agonist binding. For example, voltage-gated channels open and close based on membrane potential and are critical in the generation of action potentials by their allowance of ions to flow down established gradients. However, open channels blockers can ...
Class IV agents are slow non-dihydropyridine calcium channel blockers. They decrease conduction through the AV node , and shorten phase two (the plateau) of the cardiac action potential . They thus reduce the contractility of the heart, so may be inappropriate in heart failure.
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.
High-voltage-gated calcium channels include the neural N-type channel blocked by ω-conotoxin GVIA, the R-type channel (R stands for Resistant to the other blockers and toxins, except SNX-482) involved in poorly defined processes in the brain, the closely related P/Q-type channel blocked by ω-agatoxins, and the dihydropyridine-sensitive L-type ...