钙拮抗剂TMB-8对培养牛大脑中动脉内皮细胞Ca<sup>2+</sup>i和一氧化氮释放的影响

钙拮抗剂TMB-8对培养牛大脑中动脉内皮细胞Ca²⁺i和一氧化氮释放的影响

摘要: 目的旨在观察TMB-8对血管内皮细胞Ca²⁺i水平和NO释放的影响,探讨扩张脑血管的机制。用AR-CM-MIC阳离子测定系统,测量单个细胞内游离钙浓度(Ca²⁺i),用血红蛋白法测量一氧化氮(NO)的释放。结果表明,在细胞外钙浓度为1.3mmol·L^-1时,TMB-8 12.5及25.0μmol·L^-1对静息Ca²⁺i和甲基血红蛋白ΔE无明显影响,而50及100μmol·L^-1时可升高静息Ca²⁺i和甲基血红蛋白ΔE。表明TMB-850及100μmol·L^-1升高脑血管内皮Ca²⁺i,激活NO合酶,促进NO合成和释放,这可能是其扩张脑血管的重要机制之一。

Abstract: The effect of 8-(N,N′-diethylamino)-n-octyl-3,4,5-trimethoxybenzoate(TMB-8) on Ca²⁺i and the release of NO in cultured endothelial cells of the calf middle cerebral artery was studied by a system of measurement of ARCM-MIC, using Fura-2/AM as a fluoresent indicator and the oxyhaemoglobin method. In the presence of extracellular Ca²⁺ 1.3 mmol·L^-1, the resting Ca²⁺i and the extinction difference(ΔE) of between 401 and 410 nm were not changed by TMB-8 12.5 and 25 μmol·L^-1, but were increased by TMB-8 50 and 100 μmol·L^-1. The rise of ΔE induced by TMB-8 50 and 100 μmol·L^-1 was blocked completely by L-NAME. The elevation of Ca²⁺i was related to the release of NO. The result suggested that TMB-8 increased resting Ca²⁺i of endothelial cells of the calf middle cerebral artery and induced NO release.