1-2-dilauroylphosphatidylcholine and 1-2-dioleoylphosphatidylserine

This is a study of the morphology and transbilayer lipid distribution of human erythrocytes treated with chlorpromazine (CPZ) over extended time courses. At 0 degree C, treatment of dilauroylphosphatidyl[1-14C]choline-labeled erythrocytes with 120 microM CPZ produced an immediate stomatocytic transformation (t1/2 < 5 min) with no concurrent change in transbilayer distribution of radiolabeled lipid, as determined by bovine serum albumin extractability. At 37 degrees C, CPZ treatment of cells produced two sequential morphological effects: immediate stomatocytosis (t1/2 < 1 min) with no concurrent change in radiolabel transbilayer distribution, followed by gradual increase in stomatocytic extent over several hours, with concurrent redistribution of radiolabeled lipid to the inner monolayer. Cells pretreated with vanadate at 37 degrees C exhibited a triphasic morphological response: CPZ produced immediate stomatocytosis, followed by a transient reversion to echinocytes lasting about 2 h, before returning to stomatocytic morphologies over the next several hours. The echinocytic reversion was accompanied by exposure of phosphatidylserine on the cell surface, as indicated by increased activation of exogenous prothrombinase. These findings suggest that while CPZ induces transbilayer lipid redistribution over extended time periods (which may mediate the complex morphological transformations observed), the early stomatocytic response elicited by addition of CPZ is not due to lipid reorganization.

Topics: Antipsychotic Agents; Cell Size; Chlorpromazine; Erythrocytes; Humans; Membrane Lipids; Phosphatidylcholines; Phosphatidylserines; Serum Albumin, Bovine; Thromboplastin; Vanadates

Fourier transform Raman spectroscopy on artificial lipid membranes was used to study radiation-induced peroxidation processes as a function of time after radiation exposure. The time dependent intensity changes of the Raman lines of various C=C bondings were compared to results obtained by measuring conjugated dienes and by the thiobarbituric acid test for malondialdehydes. The results show that mainly the cis C=C bonds of the lipid chains are involved and, therefore, indicate that gamma-radiation induces conformational changes in the lipid chain while the mobility of the lipid chains is reduced. New Raman bands can be assigned to aldehyde products induced at the end of the peroxidation process. The immediate decrease of the =CH vibration lines was directly correlated with the formation of conjugated C=C double bonds suggesting that these vibration lines are in contrast to the C=C lines solely Raman active, when isolated C=C bonds are present. Cytochrome c (ox.) incorporated into the bilayer of the artificial membranes induced autooxidation processes not influenced by gamma-radiation. It was observed that cytochrome c (ox.)-induced changes of the relative intensity of the C=C bonds differ from those induced by gamma-radiation. These results of cytochrome c together with the inhibitory effects of the antioxidant alpha-tocopherol suggest that the radical species involved in the cytochrome c induced process might be different from the free radicals involved in the gamma-radiation-induced process.

Topics: Antioxidants; Cesium Radioisotopes; Cytochrome c Group; Fourier Analysis; Gamma Rays; Kinetics; Liposomes; Phosphatidylcholines; Phosphatidylserines; Spectrum Analysis, Raman; Time Factors; Vitamin E