大肠杆菌热稳定肠毒素诱导小鼠腹泻机制的研究。
Studies on the mechanism of Escherichia coli heat-stable enterotoxin-induced diarrhoea in mice.
作者信息
Goyal J, Ganguly N K, Mahajan R C, Garg U C, Walia B N
出版信息
Biochim Biophys Acta. 1987 Sep 11;925(3):341-6. doi: 10.1016/0304-4165(87)90200-5.
The unidirectional fluxes of Na+, Cl- and Ca2+ and activities of calmodulin in the intestinal microvillar core were studied in Escherichia coli heat-stable enterotoxin-treated mice. There was net secretion of Na+ and Cl- in toxin-treated animals, while in control animals there was net absorption of these ions. In both control and experimental animals, there was net absorption of Ca2+; however, the absorption was significantly higher (P less than 0.01) in experimental animals when compared to controls. In the presence of Ca2+-ionophore, there was a net secretion of Na+ and Cl- in controls, while the Ca2+-ionophore could not cause any change in the fluxes of these ions in experimental animals. The activity of calmodulin was significantly higher (P less than 0.01) in experimental animals. Verapamil, a calcium channel blocker, and trifluoperazine, a calmodulin inhibitor, reversed the effects of Ca2+-ionophore and heat-stable enterotoxin. These studies demonstrate that the toxin acts through Ca2+-calmodulin, and secretion of Na+ and Cl- in experimental animals is due to an increase in calcium absorption and an increase in calmodulin activity in the intestinal microvillar core.
在经大肠杆菌热稳定肠毒素处理的小鼠中，研究了肠道微绒毛核心中Na⁺、Cl⁻和Ca²⁺的单向通量以及钙调蛋白的活性。在毒素处理的动物中存在Na⁺和Cl⁻的净分泌，而在对照动物中这些离子存在净吸收。在对照动物和实验动物中，均存在Ca²⁺的净吸收；然而，与对照组相比，实验动物中的吸收显著更高（P小于0.01）。在存在Ca²⁺离子载体的情况下，对照组中存在Na⁺和Cl⁻的净分泌，而Ca²⁺离子载体在实验动物中不会引起这些离子通量的任何变化。实验动物中钙调蛋白的活性显著更高（P小于0.01）。钙通道阻滞剂维拉帕米和钙调蛋白抑制剂三氟拉嗪可逆转Ca²⁺离子载体和热稳定肠毒素的作用。这些研究表明，毒素通过Ca²⁺-钙调蛋白起作用，实验动物中Na⁺和Cl⁻的分泌是由于肠道微绒毛核心中钙吸收增加和钙调蛋白活性增加所致。
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