Fluorescence anisotropy changes in platelet membranes during activation.
Fluorescence anisotropy changes in platelet membranes during activation.
复制标题
激活过程中血小板膜的荧光各向异性变化。
作者：
M. Steiner;E. Lüscher
通过两种荧光探针评估血小板膜成分的动态变化，即阴离子通道阻断剂 4,4'-二异硫氰基-2,2'-二苯乙烯二磺酸 (DIDS) 和芘丁酰肼 (SPBH) 的膜非渗透性水苏糖衍生物。在用任一荧光团处理的完整血小板中测量荧光各向异性 r。在非聚集条件下，凝血酶、花生四烯酸和 ADP 激活血小板会在 60-120 秒内增加 DIDS 的各向异性值。 8-10 分钟后缓慢恢复至基线值。在前 60 秒内，凝血酶产生了 r 的初始短暂减少。其效果是特定的，因为灭活的酶不会引起任何变化。后者也可以通过从血小板悬浮液中去除 Ca2+ 来预防。用 SPBH（一种插入膜脂质小叶中的荧光团）处理血小板，揭示了在前 120 秒内激活诱导的荧光各向异性增加。当凝血酶和 ADP 为兴奋剂时，r 值会持续下降 6-8 分钟。血小板预暴露于秋水仙碱并没有显着改变任一荧光团的荧光各向异性模式，但细胞松弛素 B 几乎完全抑制这种变化。这些发现被解释为证明脂质双层具有更大的运动自由度，但刺激血小板后膜蛋白的该参数会降低。
Dynamic changes in platelet membrane components were evaluated by two fluorescent probes, the anion channel blocker 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS) and the membrane-impermeant stachyose derivative of pyrenebutyryl hydrazide (SPBH). Fluorescence anisotropy, r, was measured in intact platelets treated with either fluorophore. Activation of platelets by thrombin, arachidonic acid, and ADP under nonaggregating conditions increased the anisotropy values of DIDS within 60-120 s. A slow return to base-line values occurred after 8-10 min. Thrombin produced an initial transient reduction of r during the first 60 s. Its effect was specific as inactivated enzyme did not induce any changes. The latter could also be prevented by omitting Ca2+ from the platelet suspension. Treatment of platelets with SPBH, a fluorophore inserted into the lipid leaflet of membranes, revealed an activation-induced increase of its fluorescence anisotropy during the first 120 s. It was followed by a 6-8 min lasting decline of r when thrombin and ADP were the stimulants. Preexposure of platelets to colchicine did not change significantly the fluorescence anisotropy pattern of either fluorophore, but cytochalasin B inhibited such changes almost completely. The findings are interpreted as demonstrating greater motional freedom in the lipid bilayer but a decrease in this parameter in membrane proteins upon stimulation of platelets.
血小板蛋白组织：通过膜渗透性交联试剂处理进行分析。
影响因子：
20.3
作者：
Davies,GE;Palek,J
通讯作者：
Palek,J
DOI：
--
发表时间：
1982
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Howard,L;Shulman,S;Sadanandan,S;Karpatkin,S
通讯作者：
Karpatkin,S