Kawada N, Tran-Thi T A, Klein H, Decker K
Biochemisches Institut, Universität Freiburg, Germany.
Eur J Biochem. 1993 Apr 15;213(2):815-23. doi: 10.1111/j.1432-1033.1993.tb17824.x.
We have studied the contractility of liver sinusoidal stellate (Ito) cells stimulated with endothelin 1, nitric-oxide donors and eicosanoids. Contraction and relaxation of stellate cells were detected by the use of a silicone-rubber method that revealed the traction forces exerted by these cells. Endothelin 1 was a strong elicitor for stellate-cell contraction. 78, 55, 59 and 56% of stellate cells were contracted 2.5, 5, 10 and 20 min, respectively, after exposure to 10 nM endothelin 1. The effect of endothelin 1 was dose dependent and still detectable at an endothelin 1 concentration of 100 pM. Concomitantly, an endothelin-dependent formation of inositol phosphates was apparent; values of InsP, InsP2, and InsP3 were 881 +/- 99%, 1965 +/- 368%, and 791 +/- 120% of control, respectively, 20 min after addition of 10 nM endothelin 1. In addition, endothelin 1 caused a transient increase of [Ca2+]i in stellate cells from a basal value of 121 +/- 9 nM to maximal 1015 +/- 86 nM. These endothelin-1 effects were much stronger than those of the thromboxane-A2 analogue U46619 and of prostaglandin F2 alpha. In contrast, Iloprost, prostaglandin E2, and sodium nitroprusside promoted stellate-cell relaxation; for example, 82, 83 and 71% of stellate cells relaxed 5, 10, and 20 min, respectively, after addition of 500 microM sodium nitroprusside to contacted cells. Prostaglandin E2 and Iloprost led to elevation of cAMP levels in stellate cells from a basal value of 9.2 +/- 0.8 pmol/well to 55.1 +/- 8.0 and 122.2 +/- 12.2 pmol/well 10 min after addition of prostaglandin E2 (5 microM) and Iloprost (5 microM), respectively, in the presence of 3-isobutyl-1-methylxanthine (0.5 mM). However, sodium nitroprusside was a trigger for cGMP accumulation. Intracellular cGMP increased from a basal value of 0.9 +/- 0.07 pmol/well to 13.4 +/- 6.7 pmol/well 10 min after addition of 500 microM sodium nitroprusside into the medium. It is interesting that Iloprost and sodium nitroprusside also induced the disappearance of actin stress fibers in contracted cells; F-actin stress fibers became less numerous and de-aggregated; more than 90% of stellate cells were void of stress fibers after 10 microM Iloprost treatment for 30 min. Thus, endothelin 1, eicosanoids and sodium nitroprusside are able to modulate the contractility of stellate cells.(ABSTRACT TRUNCATED AT 400 WORDS)
我们研究了内皮素-1、一氧化氮供体和类花生酸刺激下肝窦状星状（伊藤）细胞的收缩性。通过使用硅胶橡胶法检测星状细胞的收缩和舒张，该方法可显示这些细胞施加的牵引力。内皮素-1是星状细胞收缩的强烈诱导剂。暴露于10 nM内皮素-1后，分别在2.5、5、10和20分钟时，78%、55%、59%和56%的星状细胞发生收缩。内皮素-1的作用呈剂量依赖性，在100 pM的内皮素-1浓度下仍可检测到。同时，明显出现了内皮素依赖性的肌醇磷酸形成；添加10 nM内皮素-1 20分钟后，InsP、InsP2和InsP3的值分别为对照值的881±99%、1965±368%和791±120%。此外，内皮素-1使星状细胞内的[Ca2+]i从基础值121±9 nM短暂升高至最大值1015±86 nM。这些内皮素-1的作用比血栓素A2类似物U46619和前列腺素F2α的作用要强得多。相比之下，伊洛前列素、前列腺素E2和硝普钠促进星状细胞舒张；例如，向收缩的细胞中添加500 μM硝普钠后，分别在第5、10和20分钟时，82%、83%和71%的星状细胞发生舒张。前列腺素E2和伊洛前列素使星状细胞中的cAMP水平升高，在存在3-异丁基-1-甲基黄嘌呤（0.5 mM）的情况下，分别添加前列腺素E2（5 μM）和伊洛前列素（5 μM）10分钟后，cAMP水平从基础值9.2±0.8 pmol/孔分别升高至55.1±8.0和122.2±12.2 pmol/孔。然而，硝普钠是cGMP积累的触发因素。向培养基中添加5
