Wednesday, December 10, 2014

"Magnesium: Nature's Physiologic Calcium Blocker". American Heart Journal

"Magnesium: Nature's Physiologic Calcium Blocker". American Heart Journal

Ionic calcium is antagonized by magnesium ions in the nervous system. Because of this, bioavailable supplements of magnesium, possibly including magnesium chloridemagnesium lactate, and magnesium aspartatemay increase or enhance the effects of calcium channel blockade.[21]

 Iseri LT, French JH (1984). "Magnesium: Nature's Physiologic Calcium Blocker". American Heart Journal 108 (1): 188–193. doi:10.1016/0002-8703(84)90572-6PMID 6375330

Magnesium ions (Mg2+) bind to the C-terminal EF-hand to inhibit CaV1.2 channels, thereby reducing Ca2+ influx to maintain the intracellular Ca2+ at low levels77. Supplement of Mg2+ during global ischemia resulted in myocardial protection and improved functional recovery78. These evidences suggest that calcineurin serves as a key modulator of Ca2+-dependent pathways via regulation of CaV1.2 activities and in turn mediates the pathological electrical remodelling in cardiac hypertrophy.

Magnesium as a calcium channel blocker 
  • Calcium flooding into a blood vessel endothelial cell, will trigger off a signalling cascade that will lead to increased vascular tone (increased blood pressure)174.
  • With low intakes or magnesium or insulin resistance or both, extracellular (blood) and intracellular levels of magnesium will be compromised (see below).
  • Suboptimally low extracellular levels of magnesium will allow the calcium channels to stay open allowing an influx of calcium into cells. Having an optimal level of magnesium, allows this mineral to act as a calcium channel blocker.

Low magnesium levels and endothelial cell damage 
  • As mentioned above, suboptimal intakes of magnesium will result in unopposed influx of calcium leading to increasing intracellular calcium levels.

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