Bondy S C, McKee M, Davoodbhoy Y M
Southern Occupational Health Center, University of California, Irvine 92717.
Biochim Biophys Acta. 1990 Jul 24;1026(2):213-9. doi: 10.1016/0005-2736(90)90066-w.
Synaptosomal membrane order has been studied by analysis of light depolarization by fluorescent dyes intercalated within membranes following exposure to various environmental toxicants. Two probes were explored: 1,6-diphenyl-1,3,5-hexatriene (DPH), signaling predominantly from the lipid-rich membrane core, and 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH), reporting from the more hydrophilic membrane surface. Chlordecone, a neurotoxic insecticide, decreased the anisotropy of either dye and this change could be prevented by prior treatment of synaptosomes with ganglioside GM1 but not alpha-tocopherol. Exposure to an iron-ascorbic acid oxidizing mixture enhanced synaptosomal membrane order and this effect was blocked by preincubation with alpha-tocopherol but not ganglioside GM1. While these interactions may have partially reflected additive anisotropy changes, the protective agents were also effective at concentrations where they did not in themselves modulate membrane order. Methyl mercuric chloride at concentrations up to 100 microM had no discernable effect upon membrane order. It is suggested that these changes in membrane order may underlie some of the previously reported variations in the content of ionic calcium and in the leakiness of synaptosomes.
通过分析暴露于各种环境毒物后嵌入膜内的荧光染料引起的光去极化，研究了突触体膜的有序性。研究了两种探针：1,6-二苯基-1,3,5-己三烯（DPH），主要从富含脂质的膜核心发出信号；1-[4-(三甲氨基)苯基]-6-苯基-1,3,5-己三烯（TMA-DPH），从更亲水的膜表面发出信号。氯丹，一种神经毒性杀虫剂，降低了两种染料的各向异性，这种变化可以通过用神经节苷脂GM1预先处理突触体来预防，但不能用α-生育酚预防。暴露于铁-抗坏血酸氧化混合物会增强突触体膜的有序性，这种效应会被α-生育酚预孵育阻断，但不会被神经节苷脂GM1阻断。虽然这些相互作用可能部分反映了加性各向异性变化，但保护剂在它们本身不调节膜有序性的浓度下也有效。浓度高达100微摩尔的甲基汞对膜有序性没有明显影响。有人认为，膜有序性的这些变化可能是先前报道的离子钙含量和突触体渗漏变化的一些原因。
