Easton T G, Valinsky J E, Reich E
Cell. 1978 Mar;13(3):475-86. doi: 10.1016/0092-8674(78)90321-5.
With the exception of certain blood cells considered in the accompanying paper (Valinsky, Easton and Reich, 1978), merocyanine 540 (MC 540), a fluorescent membrane probe, selectively strains the membranes of a wide variety of electrically excitable cells, but not those of nonexcitable cells. This reaction is Ca2+-dependent when staining is performed in buffered iso-osmotic sucrose, Ca2+-independent when staining proceeds at high ionic strength, inhibited by La3+ and sodium Suramin, enhanced by controlled, low level photosensitization of cell-associated dye and essentially irreversible. These characteristics of the staining reaction depend upon the maintenance of both cell viability and a normal unperturbed membrane structure. Although the mechanisms involved in the staining specificity remain unknown, observation of MC 540 partitioning between benzene and water in model reactions indicates that dye transport into hydrophobic solvents is accompanied by the formation of stoichiometric complexes with cations and phospholipids. These results may suggest the existence of specific, possibly phospholipid-rich membrane domains that mediate complex formation with MC 540 in excitable cells; comparable domains either would not exist, or would be inaccessible at the external surfaces of nonexcitable cells.
除了随附论文（瓦林斯基、伊斯顿和赖克，1978年）中所考虑的某些血细胞外，荧光膜探针部花青540（MC 540）可选择性地使多种电兴奋性细胞的膜染色，但不会使非兴奋性细胞的膜染色。当在缓冲等渗蔗糖中进行染色时，这种反应依赖于Ca2+；当在高离子强度下进行染色时，则不依赖于Ca2+，该反应受到La3+和苏拉明钠的抑制，细胞相关染料的可控低水平光致敏作用可增强该反应，且基本上是不可逆的。染色反应的这些特性取决于细胞活力和正常未受干扰的膜结构的维持。尽管染色特异性所涉及的机制尚不清楚，但在模型反应中观察到MC 540在苯和水之间的分配表明，染料向疏水溶剂中的转运伴随着与阳离子和磷脂形成化学计量复合物。这些结果可能表明，在兴奋性细胞中存在特定的、可能富含磷脂的膜结构域，介导与MC 540的复合物形成；在非兴奋性细胞的外表面，类似的结构域要么不存在，要么无法接近。
