Simultaneous measurements of K+ and calcein release from liposomes and the determination of pore size formed in a membrane
スポンサーリンク
概要
- 論文の詳細を見る
<p>The changes induced by biologically active substances in the permeability to K+ and calcein of liposomes composed of egg phosphatidylcholine and cholesterol were measured simultaneously in order to rapidly screen the sizes of pores formed in a membrane, using different sized markers. The substances examined in the present study were classified into three types based on differences in the rates at which K+ and calcein were released. The first type released only K+, and included gramicidin A. The second type predominantly released K+, preceding the release of calcein, and included amphotericin B and nystatin. The third type, including antimicrobial peptides, such as gramicidin S, alamethicin, and melittin, and several membrane-active drugs, like celecoxib (non-steroidal anti-inflammatory drug), 1-dodecylazacycloheptan-2-one (named azone; skin permeation enhancer), and chlorpromazine (tranquilizer), caused the release of K+ and calcein simultaneously. Thus, the sizes of pores formed in a liposomal membrane increased in the following order: types one, two, and three. We determined the size more precisely by conducting an osmotic protection experiment, measuring the release of calcein in the presence of osmotic protectants of different sizes. The radii of pores formed by the second type, amphotericin B and nystatin, were 0.36 - 0.46 nm, while the radii of pores formed by the third type were much larger, 0.63 - 0.67 nm or more. The permeability changes induced by substances of the third type are discussed in connection with a transient pore formed in a lipid packing mismatch taking place during the phase transition of dipalmitoylphosphatidylcholine liposomes.</p>
- 2007-05-10
著者
-
Katsu Takashi
Graduate School Of Medicine Dentistry And Pharmaceutical Sciences Okayama Univ. Tsushima Okayama 700
-
Imamura Tomonori
Graduate School Of Medicine Dentistry And Pharmaceutical Sciences Okayama University
-
Katsu Takashi
Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
関連論文
- Structure-Activity Relationship of Polymyxin B Heptapeptide and Analogs
- Porphyrin-Induced Photogeneration of Hydrogen Peroxide Determined Using the Luminol Chemiluminescence Method in Aqueous Solution : A Structure-Activity Relationship Study Related to the Aggregation of Porphyrin
- The Influence of Aggregation of Porphyrins on the Efficiency of Photogeneration of Hydrogen Peroxide in Aqueous Solution
- In Situ Monitoring of Photodynamic Inactivation of the Membrane Functions of Bacteria Using Electrochemical Sensors
- Application of an Oxygen Electrode to Evaluate Superoxide Anion-scavenging Ability
- Precise Size Determination of Amphotericin B and Nystatin Channels Formed in Erythrocyte and Liposomal Membranes Based on Osmotic Protection Experiments
- Simultaneous measurements of K+ and calcein release from liposomes and the determination of pore size formed in a membrane
- Cyclic β-Sheet Antimicrobial Peptides with Environment-sensitive Fluorophores : Photophysical Properties and Molecular Orientation in Lipid Bilayers