Sjögren A, Edvinsson L
Magnesium. 1986;5(2):66-75.
The vasomotor effects of magnesium ions and the calcium entry blockers nifedipine and verapamil have been studied in isolated feline cerebral, coronary and femoral arteries preconstricted by 124 mM potassium or 3 microM prostaglandin F2 alpha (PGF2 alpha). The order of potency for eliciting relaxation was: nifedipine greater than verapamil greater than magnesium. Magnesium showed the same profile of action as the calcium entry blockers in cerebral and coronary arteries, while the maximum relaxation obtained by magnesium was significantly smaller in femoral arteries constricted by potassium as compared with that of nifedipine (p less than 0.001) and verapamil (p less than 0.01). Besides this relaxant effect, magnesium was found to act as a constrictor during certain conditions; addition of magnesium to femoral arteries which had been preconstricted by PGF2 alpha in a magnesium-free solution resulted in relaxation in low concentrations and contraction at higher concentrations. In separate experiments, a raised extracellular concentration of magnesium was found to enhance the constrictor response to PGF2 alpha in femoral but not in coronary arteries. Cerebral arteries showed a pattern of reaction that was somewhat different from that observed in peripheral arteries. The level of maximum relaxation by magnesium in cerebral arteries was twice that found in peripheral arteries. Cerebral arteries were significantly more sensitive to verapamil than peripheral arteries.
镁离子以及钙通道阻滞剂硝苯地平和维拉帕米对血管运动的影响已在分离的猫脑动脉、冠状动脉和股动脉中进行了研究，这些动脉预先由124 mM钾或3 microM前列腺素F2α（PGF2α）收缩。引起舒张的效力顺序为：硝苯地平＞维拉帕米＞镁。在脑动脉和冠状动脉中，镁与钙通道阻滞剂表现出相同的作用模式，而在由钾收缩的股动脉中，镁获得的最大舒张程度与硝苯地平相比显著较小（p＜0.001），与维拉帕米相比也显著较小（p＜0.01）。除了这种舒张作用外，还发现镁在某些情况下起收缩作用；在无镁溶液中预先由PGF2α收缩的股动脉中加入镁，低浓度时导致舒张，高浓度时导致收缩。在单独的实验中，发现细胞外镁浓度升高会增强股动脉对PGF2α的收缩反应，但对冠状动脉没有影响。脑动脉表现出的反应模式与外周动脉中观察到的有所不同。镁在脑动脉中的最大舒张水平是在外周动脉中发现的两倍。脑动脉对维拉帕米的敏感性明显高于外周动脉。
