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Melatonin inhibits vasospastic action of oxidized low‐density lipoprotein in human umbilical arteries
Author(s) -
Okatani Yuji,
Wakatsuki Akihiko,
Watanabe Kazushi,
Ikenoue Nobuo,
Fukaya Takao
Publication year - 2000
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1034/j.1600-079x.2000.290202.x
Subject(s) - melatonin , endocrinology , medicine , umbilical artery , nitric oxide , preeclampsia , chemistry , low density lipoprotein , antioxidant , mannitol , gestation , cholesterol , biology , biochemistry , pregnancy , genetics
We evaluated the antioxidant property of melatonin in countering the vasospastic effect of oxidized low‐density lipoprotein (ox‐LDL), which has been reported to be the most important risk factor for atherosclerosis and also may be linked to preeclampsia. Helical sections of umbilical arteries were obtained from human placentas at elective cesarean deliveries between 37 and 39 weeks of gestation. Changes in maximal tension induced by potassium chloride were measured in arterial sections with intact endothelium. ox‐LDL (200 or 300 μg protein/mL) increased vascular tension by 15.6±2.3 or 31.9±4.0%, respectively. In contrast, native LDL only slightly increased vascular tension (2.7±1.0% for 200 μg protein/mL and 6.0±1.7% for 300 μg protein/mL). Pretreatment with L‐N G ‐monomethyl‐arginine (2×10 −4 M) significantly reduced the vasospastic effect of ox‐LDL, as did pretreatment with mannitol (30 mM). Melatonin (10 μM) significantly reduced the vasospastic effect of ox‐LDL. These findings suggest that ox‐LDL potentiates vascular tension in the human umbilical artery, possibly by suppressing endothelial synthesis of nitric oxide. Melatonin significantly suppressed the vasospastic effect of ox‐LDL, probably because it scavenges hydroxyl radical arising from ox‐LDL.