A STRUCTURAL AND KINETIC-STUDY BY ENERGY DISPERSION X-RAY-DIFFRACTION- INTERACTION BETWEEN 1,4-DIHYDROPYRIDINES AND BIOLOGICAL-MEMBRANES

Application of energy dispersive X-ray diffraction to the study of the main transition phase of the pure and doped DMPC (L alpha-dimyristoyl phosphotidylcholine; -ditetradecanoyl-sn-glycero-3-phosphatidylcholine ) bilayers is reported. The aim is to provide an investigative tool to follow the structural variation induced in these systems by temperatu re and by insertion of doping substances. Hydrophobic compounds such a s 1,4-dihydropyridines are used as doping molecules; Nifedipine and La cidipine show different physical-chemical properties, modifying in a d ifferent way the membrane bilayer and its main transition phase. The r esults show that this technique is useful for studying these kinds of systems (membrane bilayer or biopolymer), giving information on struct ural variations that occur in a relatively short time. (C) 1998 Elsevi er Science B.V.