Yoshimi H, Hirata Y, Takata S, Takagi Y, Fukuda Y, Kuramochi M, Omae T
Department of Medicine, National Cardiovascular Center Hospital, Osaka, Japan.
Biochem Biophys Res Commun. 1988 Jun 30;153(3):1068-75. doi: 10.1016/s0006-291x(88)81337-8.
Using fura-2-loaded rat vascular smooth muscle cells (VSMCs) in culture, we have attempted to partially purify and characterize yet unidentified factor(s) from normal human plasma that stimulates cytoplasmic free Ca2+ concentration ([Ca2+]i). The plasma extract caused an immediate and transient increase of [Ca2+]i in a dose-dependent manner, of which effect was not prevented by pretreatment with either any of receptor antagonists for -adrenergic agonist, angiotensin II, arginine vasopressin, serotonin, thromboxane A2, or with EGTA and nifedipine. This novel plasma factor(s) was heat-stable and completely inactivated by pronase E, suggesting its protein nature. Furthermore, plasma extracts dose-dependently stimulated the accumulation of [3H] inositol phosphates in rat VSMCs. Sephadex G-50 gel chromatography of plasma extracts resolved one major component (mol wt 13,000) and two minor components with larger (greater than 30,000) and smaller (3,000) mol wt. Present study demonstrates the presence of hitherto unidentified plasma factor(s) with size heterogeneity capable of stimulating both mobilization of [Ca2+]i and breakdown of phosphatidylinositol-4,5-biphosphates in rat VSMCs.
利用培养的用fura - 2负载的大鼠血管平滑肌细胞（VSMC），我们试图从正常人血浆中部分纯化并鉴定一种尚未明确的因子，该因子可刺激细胞质游离钙离子浓度（[Ca2 +]i）。血浆提取物以剂量依赖的方式引起[Ca2 +]i立即且短暂的增加，用α - 肾上腺素能激动剂、血管紧张素II、精氨酸加压素、5 - 羟色胺、血栓素A2的任何一种受体拮抗剂预处理，或用乙二醇双四乙酸（EGTA）和硝苯地平预处理，均不能阻止这种效应。这种新的血浆因子对热稳定，且被链霉蛋白酶E完全灭活，提示其蛋白质性质。此外，血浆提取物以剂量依赖的方式刺激大鼠VSMC中[3H]肌醇磷酸的积累。血浆提取物的葡聚糖凝胶G - 50柱层析分离出一个主要成分（分子量13,000）以及两个分子量较大（大于30,000）和较小（3,000）的次要成分。本研究证明存在一种迄今未明确的血浆因子，其大小具有异质性，能够刺激大鼠VSMC中[Ca2 +]i的动员以及磷脂酰肌醇 - 4,5 - 二磷酸的分解。
