Robello M, Gliozzi A
Dipartimento di Fisica dell'Università di Genova, Italy.
Biochim Biophys Acta. 1989 Jun 26;982(1):173-6. doi: 10.1016/0005-2736(89)90189-2.
A cooperative phenomenon showing a structural change in the organization of bilayer lipid membranes at a critical value of the applied electric field is presented. The transition is characterized by a sharp increase in conductance. The phenomenon can be observed under current-clamp conditions (rather than the usual voltage-clamp conditions) to avoid rupturing the membrane. At a critical potential value the conductance increases and therefore the potential decreases to keep the current constant. Results refer to membranes made of egg phosphatidylcholine (PC), diphytanoylphosphatidylcholine and cholesterol/egg PC. It is found that the critical potential at which the transition occurs depends dramatically on pH and ionic concentration, indicating that the electrical properties of the external surface determine the major characteristics of such a transition.
本文提出了一种合作现象，即在施加电场的临界值时，双层脂质膜的组织结构会发生结构变化。这种转变的特征是电导急剧增加。为避免膜破裂，可在电流钳制条件下（而非通常的电压钳制条件）观察到该现象。在临界电位值时，电导增加，因此电位降低以保持电流恒定。结果涉及由鸡蛋磷脂酰胆碱（PC）、二植烷酰磷脂酰胆碱以及胆固醇/鸡蛋PC制成的膜。研究发现，发生转变的临界电位极大地取决于pH值和离子浓度，这表明外表面的电学性质决定了这种转变的主要特征。
