The alterations of lipid bilayer fluidity induced by newly synthesized phenothiazine derivative.
Using fluorescence spectroscopy, calorimetry and ESR the interactions of the phenothiazine derivative 2-trifluoromethyl-10-(4-[methylsulfonylamid]buthyl)-phenothiazine (FPhMS) with lipids were studied. Calorimetry showed biphasic effect of FPhMS on main phase transition of DPPC. At molar ratios up to 0.06 drug induced decrease of transition temperature and enthalpy, while at higher concentrations it caused subsequent increase of these parameters. For all concentrations studied we observed gradual broadening of transition peaks. Fluorescence polarization revealed that in FPhMS/lipid mixtures, order in bilayers is decreased in the gel state and increased in the liquid crystalline state. ESR experiment showed that at molar ratio of 0.06, FPhMS reduces the mobility of spin probes located in both polar and hydrophobic regions. Comparing observed effects with those reported for cholesterol/lipid mixtures, we conclude that at higher concentrations FPhMS presumably induces a new mode of bilayer packing. This structure is less co-operative than an unperturbed bilayer, but locally the mobility of lipid molecules is decreased.
Department of Biophysics, Wrocław Medical University, ul. Chałubińskiego 10, 50-368, Wrocław, Poland. hendrich@biofiz.am.wroc.pl
Andrzej B
AB
Hendrich
Olga
O
Wesołowska
Małgorzata
M
Komorowska
Noboru
N
Motohashi
Krystyna
K
Michalak
D002152:Calorimetry, Differential Scanning; D002463:Cell Membrane Permeability / Q000187:drug effects; D005454:Fluorescence Polarization; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D008560:Membrane Fluidity; D010640:Phenothiazines / Q000737:chemistry* / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013449:Sulfonamides / Q000737:chemistry* / Q000494:pharmacology
C465764:2-trifluoromethyl-10-(4-(methylsulfonylamido)butyl)phenothiazine; D008051:Lipid Bilayers; D008081:Liposomes; D010640:Phenothiazines; D013449:Sulfonamides