血管内皮细胞释放的血管舒张因子除一氧化氮和前列腺素外 ,尚可能存在着第三种因子 ,即内皮依赖性超极化因子。这种因子可引起平滑肌膜电位的超极化和舒张 ,其作用不能被一氧化氮合酶和环氧酶抑制剂阻断 ,但可被钾通道阻断剂抵抗。内皮依赖性超极化因子的化学本质目前尚不清楚。 Vasodilator released by vascular endothelial cells In addition to nitric oxide and prostaglandins, there may be a third factor, endothelium-dependent hyperpolarization factor. This factor can cause hyperpolarization and relaxation of smooth muscle potential, its role can not be blocked by nitric oxide synthase and cyclooxygenase inhibitors, but can be resistance to potassium channel blockers. The chemical nature of endothelium-dependent hyperpolarizing factors is not clear.