Okatani Y, Wakatsuki A, Morioka N, Watanabe K
Department of Obstetrics and Gynecology, Kochi Medical School, Oko, Nankoku, Japan.
J Pineal Res. 1999 Sep;27(2):111-5. doi: 10.1111/j.1600-079x.1999.tb00604.x.
We evaluated the antioxidant property of melatonin as it relates to the vasorelaxant effect of peroxynitrite (ONOO ), a reaction product of superoxide anion radical (O2(-)) and nitric oxide (NO), on the human umbilical artery. Helical sections of umbilical arteries were obtained from human placentas at elective cesarean delivery between weeks 37 and 39 of gestation. Changes in maximal tension induced by potassium chloride were measured in arterial sections with intact endothelium. Sections were treated with 3-morpholinosydomine (SIN-1), which releases O2(-) and NO simultaneously, with or without pre-treatment either with hemoglobin (3 microM) or melatonin (0.1-10 microM). SIN-1 produced a significant dose-dependent relaxation of vascular tension. Pre-treatment with hemoglobin did not affect SIN-1-induced relaxation. Melatonin significantly reduced the vasorelaxant effect of SIN-1 in a concentration-dependent manner. These findings indicate that ONOO attenuates vascular tension in the human umbilical artery. Melatonin significantly suppressed the vasorelaxant effect of SIN-1, possibly due to its ability to scavenge ONOO-.
我们评估了褪黑素的抗氧化特性，该特性与过氧亚硝酸根（ONOO⁻）对人脐动脉的血管舒张作用有关，过氧亚硝酸根是超氧阴离子自由基（O₂⁻*）和一氧化氮（NO）的反应产物。在妊娠37至39周选择性剖宫产时从人胎盘获取脐动脉螺旋切片。在具有完整内皮的动脉切片中测量氯化钾诱导的最大张力变化。切片用3-吗啉代 sydomine（SIN-1）处理，SIN-1可同时释放O₂⁻*和NO，处理时伴有或不伴有血红蛋白（3μM）或褪黑素（0.1 - 10μM）的预处理。SIN-1产生了显著的剂量依赖性血管张力舒张。用血红蛋白预处理不影响SIN-1诱导的舒张。褪黑素以浓度依赖性方式显著降低了SIN-1的血管舒张作用。这些发现表明，ONOO⁻减弱了人脐动脉的血管张力。褪黑素显著抑制了SIN-1的血管舒张作用，这可能归因于其清除ONOO⁻的能力。
