内皮素-1抑制质膜Ca++-ATP酶，同时伴有肝血窦内皮窗孔收缩。
Endothelin-1 suppresses plasma membrane Ca++-ATPase, concomitant with contraction of hepatic sinusoidal endothelial fenestrae.
作者信息
Yokomori Hiroaki, Oda Masaya, Ogi Mariko, Yoshimura Kazunori, Nomura Masahiko, Fujimaki Kayo, Kamegaya Yoshitaka, Tsukada Nobuhiro, Ishii Hiromasa
机构信息
Department of Internal Medicine and the Laboratory of Pathology, Kitasato Medical Center Hospital, Saitama.
出版信息
Am J Pathol. 2003 Feb;162(2):557-66. doi: 10.1016/S0002-9440(10)63849-7.
Intracytoplasmic free calcium ions (Ca++) are maintained at a very low concentration in mammalian tissue by extruding Ca++ from the cytoplasm against a steep extracellular Ca++ concentration gradient, mainly through the activity of plasma membrane Ca++ pump-ATPase. The present study aimed to elucidate how endothelin-1 (ET-1) affects the morphology of sinusoidal endothelial fenestrae and ultrastructural distribution of plasma membrane ATPases and intracytoplasmic free Ca++ in isolated rat hepatic sinusoidal endothelial cells. Sinusoidal endothelial fenestrae were observed by scanning electron microscope. Ando's electron cytochemical method was used for ultrastructural localization of Ca++-Mg++-ATPase activity, electron immunogold postembedding method for Ca++ pump-ATPase immunoactivity, and antimonate method for intracytoplasmic free Ca++. Addition of ET-1 to sinusoidal endothelial cells significantly decreased Ca++-Mg++-ATPase activity and Ca++ pump-ATPase expression and increased intracytoplasmic free Ca++ concentration, concomitant with a decrease in diameter of sinusoidal endothelial fenestrae. Co-treatment with Bosentan abolished the actions of ET-1. These results suggest that ET-1 suppresses Ca++-Mg++-ATPase activity and Ca++ pump-ATPase expression on the plasma membrane of sinusoidal endothelial fenestrae, thereby attenuating the extrusion of intracytoplasmic free Ca++ into the extracellular space, leading to an increased concentration of intracytoplasmic free calcium ions and contraction of sinusoidal endothelial fenestrae.
在哺乳动物组织中，细胞质内的游离钙离子（Ca++）通过逆着陡峭的细胞外Ca++浓度梯度将Ca++从细胞质中挤出，主要是通过质膜Ca++泵 - ATP酶的活性，从而维持在非常低的浓度。本研究旨在阐明内皮素 - 1（ET - 1）如何影响分离的大鼠肝窦状内皮细胞中窦状内皮窗孔的形态、质膜ATP酶的超微结构分布以及细胞质内游离Ca++的情况。通过扫描电子显微镜观察窦状内皮窗孔。采用安藤电子细胞化学方法对Ca++ - Mg++ - ATP酶活性进行超微结构定位，电子免疫金包埋后方法检测Ca++泵 - ATP酶免疫活性，以及锑酸盐方法检测细胞质内游离Ca++。向窦状内皮细胞中添加ET - 1可显著降低Ca++ - Mg++ - ATP酶活性和Ca++泵 - ATP酶表达，并增加细胞质内游离Ca++浓度，同时窦状内皮窗孔直径减小。与波生坦共同处理可消除ET - 1的作用。这些结果表明，ET - 1抑制窦状内皮窗孔质膜上的Ca++ - Mg++ - ATP酶活性和Ca++泵 - ATP酶表达，从而减弱细胞质内游离Ca++向细胞外空间的挤出，导致细胞质内游离钙离子浓度增加和窦状内皮窗孔收缩。
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