Role of endothelium in the responses of human intracranial arteries to a slight reduction of extracellular magnesium

Exp Physiol. 1992 Jan;77(1):209-11. doi: 10.1113/expphysiol.1992.sp003575.


The effect of a slight reduction of extracellular magnesium on the tone of precontracted small human pial arteries and the dependence of the response on the functional integrity of the vascular endothelium was investigated in vitro. A decrease in extracellular magnesium from 1.2 to 0.8 mM resulted in sustained relaxation when the endothelium was intact. When the endothelium was disrupted, the same reduction resulted in an elevation of tone. These results suggest that small changes in extracellular magnesium modulate human cerebro-arterial tone through an endothelium-derived relaxing factor rather than by altering smooth muscle tone directly.

MeSH terms

  • Acetylcholine / pharmacology
  • Adult
  • Aged
  • Cerebral Arteries / drug effects*
  • Cerebral Arteries / physiology
  • Endothelium, Vascular / drug effects*
  • Endothelium, Vascular / physiology
  • Female
  • Humans
  • In Vitro Techniques
  • Magnesium / pharmacology*
  • Magnesium Deficiency / physiopathology
  • Male
  • Middle Aged
  • Pia Mater / blood supply
  • Vasodilation / drug effects


  • Magnesium
  • Acetylcholine