ผลของแมกนีเซียมซัลเฟตต่อหลอดเลือดดำและหลอดเลือดแดงของสายสะดือมนุษย์ / ศิริจุฬาฤทธิ์ สุดประโคนเขต = Effects of magnesium sulphate on human isolated umbilical vein and artery / Sirijularid Sudpraconkate
Magnesium sulphae (MgSO4H2O) is used as an clinically anticonvulsant in the management and prevention of eclampsia, but mechanism of action is unknown. To determine whether MgSO4 relaxes isolated human umbilical vein and artery and to investigate the pathway involved, isolated human umbilical vein and artery were used in this study. MgSO4 1x10 -2 M, 2x10 -2 M significantly (P<0.05) caused relaxation of isolated human umbilica vein and artery induded by 5-HT (1x10 -6 M) and histamine (1x10 -5 M). It also inhibited vein and artery smooth muscle contraction induced by 5-HT and histamine both in Krebs-Henseleit solution and Ca2+ -free Krebs-Henseleit solution but did not significanty relax both vein and artery induded by KCl, either in Krebs-Henseleit solution or in Ca2+ -free medium. Magnesium sulphate significanty reduced cumulative dose response curve induced by CaCl2 in potassium depolarizing and BaCl2 in HCO3- and Ca2+ -free Krebs-Henseleit solution. The results obtained from this study suggested that MgSO4 caused non-specific inhibitory effect on human isolated vein and artery. The possible mechanism may be related to receptor activation rather than membrane depolarization or it may involve a decrease in [Ca2+]i by interfering with influx of calcium ions via ROC and VOC which depend on extracellular Ca2+.
