diphenylhexatriene and 1-3-di-(1-pyrenyl)propane

Intramolecular excimer formation of 1,3-di(1-pyrenyl) propane(Py-3-Py) and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) were used to evaluate the effect of ethanol on the rate and range of lateral and rotational mobilities of bulk bilayer structures of synaptosomal plasma membrane vesicles (SPMVs) from the bovine cerebral cortex. Ethanol increased the excimer to monomer fluorescence intensity ratio (I'/I) of Py-3-Py in the SPMVs. Selective quenching of both DPH and Py-3-Py by trinitrophenyl groups was used to examine the range of transbilayer asymmetric rotational mobility and the rate and range of transbilayer asymmetric lateral mobility of SPMVs. Ethanol increased the rotational and lateral mobility of the outer monolayer more than of the inner one. Thus ethanol has a selective fluidizing effect within the transbilayer domains of the SPMVs. Radiationless energy transfer from the tryptophans of membrane proteins to Py-3-Py was used to examine both the effect of ethanol on annular lipid fluidity and protein distribution in the SPMVs. Ethanol increased annular lipid fluidity and also caused membrane proteins to cluster. These effects on neuronal membranes may be responsible for some, though not all, of the general anesthetic actions of ethanol.

Topics: Animals; Cattle; Cell Membrane; Cerebral Cortex; Diphenylhexatriene; Ethanol; Fluorescent Dyes; Fluorometry; Lipid Bilayers; Membrane Fluidity; Membrane Proteins; Pyrenes; Synaptosomes; Trinitrobenzenesulfonic Acid

The aim of this study was to provide the basis to further examine the mode of action of ethanol. Fluorescent probes reported to have different membrane mobilities were used to evaluate the effect of dimyristoylphosphatidylethanol (DMPEt) on the lateral and rotational mobilities of liposome lipid bilayers. An experimental procedure, based on the selective quenching of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1,3-di(1-pyrenyl)propane (Py-3-Py) by trinitrophenyl groups, was used. DMPEt increased the bulk lateral and rotational mobilities, and had a greater fluidizing effect on the outer than the inner monolayer. These effects of DMPEt on liposomes may be responsible for some, but not all, of the general anesthetic actions of ethanol.

Topics: Animals; Cell Line; Cell Membrane; Cells, Cultured; Central Nervous System Depressants; Diphenylhexatriene; Ethanol; Glycerophospholipids; Hybridomas; Lipid Bilayers; Liposomes; Membrane Fluidity; Pyrenes; Thiazines

The primary aim of this study was to investigate the skin permeation-enhancing mechanism of HPE-101 using erythrocyte ghost cells prepared from human whole blood as a biomembrane model. The extent of hemolysis of erythrocytes induced by HPE-101 was measured using a spectrophotometer at 540nm. The effect of HPE-101 on lipid fluidity was examined by observing the change of intramolecular excimer formation and fluorescence polarization using an intramolecular probe (1,3-bis(pyrene) propane) and a lipid probe (1,6-diphenyl 1,3,5-hexatriene), respectively. Hemolysis of erythrocytes was observed at 0.01mM and completed at 1.0mM of HPE-101. The fluorescence polarization of the ghost membrane decreased with the addition of HPE-101, whereas the intramolecular excimer formation increased. HPE-101 thus enhanced the rotational mobility and the lateral diffusion, thereby decreasing the microviscosity of ghost membranes, implying that HPE-101 increases the lipid fluidity of ghost membranes. Therefore, HPE-101 seems to cause an increase in fluidity of the lipid bilayers in the stratum corneum of the skin, resulting in the reduction of diffusion resistance.

Topics: Adjuvants, Pharmaceutic; Binding Sites; Diffusion; Diphenylhexatriene; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Erythrocyte Membrane; Fluorescence Polarization; Hemolysis; Humans; Korea; Lipid Bilayers; Membrane Fluidity; Models, Biological; Molecular Probes; Pyrenes; Pyrroles; Skin; Spectrophotometry; Viscosity

2,2-Bis(p-chlorophenyl)-1,1-dichloroethylene (DDE) interaction with model and native membranes was studied by means of fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), probing the bilayer core, and by intramolecular excimerization of 1,3-di(1-pyrenyl) propane (Py(3)Py), probing the outer regions of the bilayer. In the gel phase of DMPC bilayers, DDE induces concentration-dependent fluidizing effects into the hydrophobic core, but no effects are detected in the outer regions of the membrane, as evaluated by DPH and Py(3)Py, respectively. Regarding the fluid phase, DDE has no apparent effect on the bilayer center, but it induces a limited ordering effect on the outer regions. Similar effects are described for bilayers of DPPC and DSPC. Unlike DPH, Py(3)Py is very sensitive to DPPC and DSPC pretransitions, not abolished by DDE (50 microM), as opposite to the effects observed with lindane (Antunes-Madeira, M.C., Almeida, L.M. and Madeira, V.M.C. (1990) Biochim. Biophys. Acta 1022, 110-114), but similar to those observed with DDT (Antunes-Madeira, M.C., Almeida, L.M. and Madeira, V.M.C. (1991) Pestic. Sci. 33, 347-357). DDE inhibits to some extent the cholesterol-induced ordering in DMPC bilayers and high cholesterol concentrations (> or = 30 mol%) do not prevent DDE interaction, as evaluated by DPH. On the other hand, the effects of DDE reported by Py(3)Py depend on temperature and cholesterol contents of DMPC bilayers. For cholesterol levels ranging from 10 to 50 mol% and temperatures below the phase transition of DMPC, Py(3)Py fails to detect any significant effect. Nevertheless, above the phase transition, Py(3)Py detects either ordering effects of DDE at low cholesterol contents (< 30 mol%) or fluidizing effects at high cholesterol levels (> or = 30 mol%). The results in native membranes correlate reasonably with those obtained in models of synthetic lipids. Thus, DPH does not detect any apparent effect of DDE in relatively fluid native membranes of sarcoplasmic reticulum, but detects moderate disordering effects in membranes of brain microsomes and erythrocytes, i.e., membranes with high cholesterol. On the other hand, Py(3)Py reports ordering effects of DDE in fluid membranes of sarcoplasmic reticulum, an effect similar to that observed in fluid systems of synthetic lipids without or with low cholesterol. Additionally, as described for models, Py(3)Py detects disordering effects of DDE in cholesterol rich membranes, namely, brain micros

Topics: 1,2-Dipalmitoylphosphatidylcholine; Animals; Dichlorodiphenyl Dichloroethylene; Dimyristoylphosphatidylcholine; Diphenylhexatriene; Fluorescence Polarization; Hot Temperature; Membrane Fluidity; Membranes; Models, Biological; Phosphatidylcholines; Pyrenes