Department of Biochemistry, V.P. Chest Institute, Delhi-110007, India.
J Pharm Pharmacol. 2011 Sep;63(9):1175-85. doi: 10.1111/j.2042-7158.2011.01316.x. Epub 2011 Jul 15.
To evaluate the potential of a novel dihydropyrimidinone, ethyl 4-(4'-heptanoyloxyphenyl)-6-methyl-3,4-dihydropyrimidin-2-one-5-carboxylate (H-DHPM), as a calcium channel blocker, endowed with the ability to inhibit platelet aggregation effectively.
In-vitro and in-vivo studies were conducted for the determination of antiplatelet activity using adenosine diphosphate (ADP), collagen or thrombin as inducers. Calcium channel blocking activity and nitric oxide synthase (NOS) activity were monitored. Lipopolysaccharide (LPS)-mediated prothrombotic conditions were developed in rats to study the efficacy of H-DHPM to suitably modulate the inflammatory mediators such as inducible NOS (iNOS) and tissue factor. The cGMP level and endothelial NOS (eNOS) expression were checked in aortic homogenate of LPS-challenged rats pretreated with H-DHPM. The effect of H-DHPM on FeCl(3) -induced thrombus formation in rats was examined.
The concentrations of H-DHPM required to give 50% inhibition (IC50) of in-vitro platelet aggregation induced by ADP, collagen or thrombin were 98.2±2.1, 74.5±2.3 and 180.7±3.4µm, respectively. H-DHPM at a dose of 52.0±0.02mg/kg (133µmol/kg) was found to optimally inhibit ADP-induced platelet aggregation in-vivo. The level of nitric oxide was found to be up to 9±0.08-fold in H-DHPM-treated platelets in-vitro and 8.2±0.05-fold in H-DHPM-pretreated rat platelets in-vivo compared with control. OH-DHPM, the parent compound was found to be ineffective both in-vitro and in-vivo. H-DHPM-pretreated rats were able to resist significantly the prothrombotic changes caused by LPS by blunting the expression of iNOS, tissue factor and diminishing the increased level of cGMP to normal. H-DHPM enhanced the eNOS expression in aorta of rats treated with LPS. H-DHPM displayed synergy with antiplatelet activity of aspirin even at lower doses. H-DHPM was found to inhibit the LPS-induced platelet aggregation in younger as well as older rats. H-DHPM exhibited the ability to markedly decrease FeCl(3) -induced thrombus formation in rats.
H-DHPM has the attributes of a promising potent antiplatelet candidate molecule that should attract further study. H-DHPM displayed antiplatelet activity both in vivo and in vitro, which was due partially by lowering the intraplatelet calcium concentration.
评估新型二氢嘧啶酮化合物乙基 4-(4'-庚酰氧苯基)-6-甲基-3,4-二氢嘧啶-2-酮-5-羧酸酯（H-DHPM）作为钙通道阻滞剂的潜力，该化合物具有有效抑制血小板聚集的能力。
使用二磷酸腺苷（ADP）、胶原蛋白或凝血酶作为诱导剂，进行体内外研究以确定抗血小板活性。监测钙通道阻断活性和一氧化氮合酶（NOS）活性。在大鼠中建立脂多糖（LPS）介导的促血栓形成条件，以研究 H-DHPM 调节诱导型 NOS（iNOS）和组织因子等炎症介质的功效。检查 LPS 挑战的大鼠主动脉匀浆中的 cGMP 水平和内皮型 NOS（eNOS）表达，并用 H-DHPM 预处理。检查 H-DHPM 对大鼠 FeCl3 诱导的血栓形成的影响。
H-DHPM 抑制 ADP、胶原蛋白或凝血酶诱导的体外血小板聚集的 50%抑制浓度（IC50）分别为 98.2±2.1、74.5±2.3 和 180.7±3.4µm。发现 H-DHPM 以 52.0±0.02mg/kg（133µmol/kg）的剂量可最佳抑制体内 ADP 诱导的血小板聚集。发现 H-DHPM 处理的血小板中一氧化氮水平高达体外 9±0.08 倍，体内 H-DHPM 预处理的大鼠血小板中 8.2±0.05 倍，而对照则为 1 倍。母化合物 OH-DHPM 无论是在体外还是在体内都无效。H-DHPM 预处理的大鼠能够通过抑制 iNOS、组织因子的表达和将 cGMP 水平降低至正常水平来显著抵抗 LPS 引起的促血栓形成变化。H-DHPM 增强了 LPS 处理大鼠主动脉中的 eNOS 表达。H-DHPM 与阿司匹林的抗血小板活性具有协同作用，即使在较低剂量下也是如此。发现 H-DHPM 抑制年轻和老年大鼠的 LPS 诱导的血小板聚集。H-DHPM 显示出显著降低大鼠 FeCl3 诱导的血栓形成的能力。
H-DHPM 具有成为有前途的强效抗血小板候选分子的特性，这应该引起进一步的研究。H-DHPM 表现出体内和体外的抗血小板活性，部分原因是降低了血小板内钙浓度。
