Ibrahim B, Guiet-Bara A, Leveteau J, Challier J C, Vervelle C, Bara M
Laboratoire de Physiopathologie du Développement, Université P.M. Curie, Paris, France.
Magnes Res. 1995 Jun;8(2):127-35.
Magnesium has been shown to produce various effects on vascular smooth muscle, in that its absence elicits an increase in muscle tone and increases sensitivity to a number of stimulatory agonists. In the present study, the influence of MgCl2 and MgSO4 was investigated in human placental chorionic muscle cells (from arteries and veins with or without endothelium), especially on the membrane potential, Um. Classically, Um was obtained from microelectrodes inserted into smooth muscle cells through the endothelium or directly. In arteries with endothelium, the smooth muscle cells were depolarized by MgSO4 (threshold: 6 mM) and MgCl2 (threshold: 8 mM). In endothelium-free arteries, the smooth muscle cells were also depolarized by MgSO4 (threshold: 8 mM) and MgCl2 (threshold: 6 mM). Identical results were obtained with veins, but thresholds were different. The different thresholds may indicate that MgCl2 influences the cell membrane potential directly, while MgSO4 interferes first with the endothelial cells, which may act as an intermediary between the Mg2+ ions and the membrane of the smooth muscle cells.
镁已被证明对血管平滑肌有多种作用，因为缺乏镁会导致肌张力增加，并增加对多种刺激激动剂的敏感性。在本研究中，研究了MgCl₂和MgSO₄对人胎盘绒毛膜肌细胞（来自有或无内皮的动脉和静脉）的影响，特别是对膜电位Um的影响。传统上，Um是通过微电极经内皮或直接插入平滑肌细胞获得的。在有内皮的动脉中，平滑肌细胞被MgSO₄（阈值：6 mM）和MgCl₂（阈值：8 mM）去极化。在无内皮的动脉中，平滑肌细胞也被MgSO₄（阈值：8 mM）和MgCl₂（阈值：6 mM）去极化。静脉也得到了相同的结果，但阈值不同。不同的阈值可能表明MgCl₂直接影响细胞膜电位，而MgSO₄首先干扰内皮细胞，内皮细胞可能充当Mg²⁺离子和平滑肌细胞膜之间的中介。
