INFLUENCE OF THE LOCAL-ANESTHETIC TETRACAINE ON THE PHASE-BEHAVIOR AND THE THERMODYNAMIC PROPERTIES OF PHOSPHOLIPID-BILAYERS
INFLUENCE OF THE LOCAL-ANESTHETIC TETRACAINE ON THE PHASE-BEHAVIOR AND THE THERMODYNAMIC PROPERTIES OF PHOSPHOLIPID-BILAYERS
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DOI：
10.1016/s0006-3495(93)81254-2
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发表时间：
1993-11-01
影响因子：
3.4
通讯作者：
WINTER, R
中科院分区：
文献类型：
--
作者：
BOTTNER, M;WINTER, R
我们研究了局部麻醉剂丁卡因对模型生物膜1，2-dimyristoyl-sn-glycero-3-phosphocholine的热力学性质和温度和压力依赖性相行为的影响，通过使用体积测量，温度范围从0度到40度C，压力从环境压力到1000巴。的pVT测量的温度依赖性差示扫描量热法测量的补充。从这些实验中可以获得关于不同浓度的局部麻醉剂对伴随脂质相变的热力学变化的影响的信息，以及对热膨胀系数、等温压缩性和脂质在其不同相中的体积波动的影响的信息。丁卡因的掺入导致膜的整体无序，这可以从主要转变温度的降低和主要脂质相变时体积变化的减少来推断。丁卡因的加入使脂双层的膨胀系数α（p）和等温压缩系数chi（T）增大，并使α（p）和chi（T）值显著增大，同时在主相变区附近发现了脂双层的体积波动.由于丁卡因可以被视为两亲性分子的模型系统，这些结果也提供了深入了解两亲性分子对膜的物理化学作用的一般理解。实验结果进行了比较，最近的理论预测麻醉剂脂质系统的相行为，并讨论了这项研究的生物相关性。
We investigated the influence of the local anesthetic tetracaine on the thermodynamic properties and the temperature- and pressure-dependent phase behavior of the model biomembrane 1,2-dimyristoyl-sn-glycero-3-phosphocholine by using volumetric measurements at temperatures ranging from 0-degrees to 40-degrees-C and at pressures from ambient up to 1000 bar. The pVT measurements were complemented by temperature-dependent differential scanning calorimetric measurements. Information about the influence of different concentrations of the local anesthetic on the thermodynamic changes accompanying the lipid phase transitions, and on the thermal expansion coefficient, the isothermal compressibility, and the volume fluctuations of the lipids in their different phases, could be obtained from these experiments. The incorporation of tetracaine leads to an overall disordering of the membrane, as can be inferred from the depression of the main transition temperature and the reduction of the volume change at the main lipid phase transition. The expansion coefficient alpha(p) and the isothermal compressibility chi(T) of the lipid bilayer are enhanced by the addition of tetracaine and strongly enhanced values of alpha(p) and chi(T), and the lipid volume fluctuations are found in the direct neighborhood of the main phase transition region. As tetracaine can be viewed as a model system for amphiphilic molecules, these results also provide insight into the general understanding of the physicochemical action of amphiphilic molecules on membranes. The experimental results are compared with recent theoretical predictions for the phase behavior of anesthetic-lipid systems, and the biological relevance of this study is discussed.