Non-anticoagulant heparin increases endothelial nitric oxide synthase activity: role of inhibitory guanine nucleotide proteins.
Non-anticoagulant heparin increases endothelial nitric oxide synthase activity: role of inhibitory guanine nucleotide proteins.
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非抗凝肝素增加内皮一氧化氮合酶活性：抑制性鸟嘌呤核苷酸蛋白的作用。
DOI：
10.1006/jmcc.1998.0831
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Sitzmann,JV
中科院分区：
文献类型：
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作者：
Kouretas,PC;Hannan,RL;Kapur,NK;Hendrickson,R;Redmond,EM;Myers,AK;Kim,YD;Cahill,PA;Sitzmann,JV
肝素被广泛应用于临床，最近被证明具有影响血管内皮细胞的特性。我们假设肝素刺激内皮型一氧化氮合酶(ENOS)活性的机制与其抗凝特性无关，并且依赖于抑制性鸟嘌呤核苷酸调节蛋白(GI)。我们测定了肝素和不含抗凝剂的肝素衍生物N-乙酰肝素(Non-Hep)对培养的牛主动脉内皮细胞eNOS活性和血管环内皮依赖性松弛的影响。通过测定瓜氨酸和一氧化氮(NO)代谢物的生成来测定eNOS活性。肝素和非肝素呈剂量依赖性地增加基础eNOS活性(ED501.0μg/ml或0.15U/ml)，这种作用可被胃肠道蛋白抑制剂百日咳毒素(100 ng/ml)显著抑制。肝素和非HEP均可增强激动剂刺激的(乙酰胆碱，10μm)eNOS活性，而百日咳毒素可使其逆转。肝素和非HEP对胸主动脉环的收缩作用呈剂量依赖性，这种作用可被百日咳毒素、内皮失活(用脱氧胆酸钠处理)和NG-硝基-L-精氨酸甲酯(L-NAME)显著抑制。我们得出结论，肝素和非抗凝剂肝素在eNOS激活后通过一种涉及Gi-蛋白的机制诱导内皮依赖的松弛。在以内皮功能障碍为特征的情况下，给予不具有抗凝特性的肝素衍生物可能对eNOS的保存具有治疗意义。
Heparin, which is widely used clinically, has recently been shown to have specific properties affecting the vascular endothelium. We hypothesized that heparin stimulates endothelial nitric oxide synthase (eNOS) activity by a mechanism independent of its anticoagulant properties and dependent on an inhibitory guanine nucleotide regulatory protein (Gi). We determined the effect of both heparin andN-acetyl heparin (Non-Hep), a heparin derivative without anticoagulant properties, on eNOS activity in cultured bovine aortic endothelial cells and on endothelium-dependent relaxation in isolated vascular rings. The eNOS activity was determined by measuring both citrulline and nitric oxide (NO) metabolite formation. Heparin and Non-Hep dose-dependently increased basal eNOS activity (ED501.0μg/ml or 0·15 U/ml), an effect that was significantly inhibited by pertussis toxin (100 ng/ml), a Gi-protein inhibitor. Agonist-stimulated (acetylcholine, 10μm) eNOS activity was potentiated following pre-treatment with both heparin and Non-Hep and reversed by pertussis toxin. Heparin and Non-Hep induced a dose-dependent relaxation in preconstricted thoracic aortic rings, an effect that was significantly inhibited by pertussis toxin, endothelial inactivation (following treatment with sodium deoxycholate) andNG-nitro-l-arginine-methyl ester (L-NAME). We conclude that heparin and non-anticoagulant heparin induce endothelium-dependent relaxation following activation of eNOS by a mechanism involving a Gi-protein. Administration of heparin derivatives without anticoagulant properties may have therapeutic implications for the preservation of eNOS in conditions characterized by endothelial dysfunction.