Ford D A, Gross R W
Department of Medicine, Washington University, Saint Louis, MO 63110.
Proc Natl Acad Sci U S A. 1989 May;86(10):3479-83. doi: 10.1073/pnas.86.10.3479.
The present study demonstrates that rabbit aortic intimal smooth muscle cells contain the majority of their endogenous arachidonic acid mass in plasmenylethanolamine molecular species. To demonstrate the potential significance of these plasmenylethanolamines as substrates for the smooth muscle cell phospholipases that are activated during agonist stimulation, aortic rings were prelabeled with [3H]arachidonic acid and stimulated with angiotensin II. Although the specific activities of the choline and inositol glycerophospholipid pools were similar after the labeling interval, ethanolamine glycerophospholipids had a specific activity of only 20% of the specific activity of choline and inositol glycerophospholipids. Despite the marked disparity in the specific activities of these three phospholipid classes, angiotensin II stimulation resulted in similar fractional losses (35-41%) of [3H]arachidonic acid from vascular smooth muscle choline, ethanolamine, and inositol glycerophospholipid classes. Reverse-phase HPLC demonstrated that greater than 60% of the [3H]arachidonic acid released from ethanolamine glycerophospholipids after angiotensin II stimulation originated from plasmenylethanolamine molecular species. Taken together, the results demonstrate that the major phospholipid storage depot for arachidonic acid in vascular smooth muscle cells are plasmenylethanolamine molecular species which are important substrates for the phospholipase(s) that are activated during agonist stimulation.
本研究表明，兔主动脉内膜平滑肌细胞内大部分内源性花生四烯酸以缩醛磷脂酰乙醇胺分子种类的形式存在。为了证明这些缩醛磷脂酰乙醇胺作为激动剂刺激过程中被激活的平滑肌细胞磷脂酶底物的潜在重要性，用[3H]花生四烯酸对主动脉环进行预标记，并用血管紧张素II进行刺激。尽管在标记期后胆碱和肌醇甘油磷脂池的比活性相似，但乙醇胺甘油磷脂的比活性仅为胆碱和肌醇甘油磷脂比活性的20%。尽管这三类磷脂的比活性存在明显差异，但血管紧张素II刺激导致血管平滑肌胆碱、乙醇胺和肌醇甘油磷脂类中[3H]花生四烯酸的类似分数损失（35-41%）。反相高效液相色谱法表明，血管紧张素II刺激后从乙醇胺甘油磷脂释放的[3H]花生四烯酸中，超过60%来自缩醛磷脂酰乙醇胺分子种类。综上所述，结果表明血管平滑肌细胞中花生四烯酸的主要磷脂储存库是缩醛磷脂酰乙醇胺分子种类，它们是激动剂刺激过程中被激活的磷脂酶的重要底物。
