Amiodarone effects on membrane organization evaluated by fluorescence polarization
| Autor: | Romeu A. Videira, Vítor M.C. Madeira, M. L. W. Kluppel, M.C. Antunes-Madeira |
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| Rok vydání: | 1995 |
| Předmět: |
Diphenylhexatriene
Membrane Fluidity Lipid Bilayers Amiodarone Fluorescence Polarization In Vitro Techniques Mitochondria Heart Membrane Potentials chemistry.chemical_compound Microsomes polycyclic compounds Membrane fluidity Humans Medicine Lipid bilayer Phospholipids Fluorescent Dyes Membrane potential business.industry Bilayer technology industry and agriculture Membranes Artificial Intracellular Membranes Cholesterol Membrane chemistry Dipalmitoylphosphatidylcholine Biophysics lipids (amino acids peptides and proteins) Dimyristoylphosphatidylcholine Cardiology and Cardiovascular Medicine business Fluorescence anisotropy |
| Zdroj: | International Journal of Cardiology. 48:211-218 |
| ISSN: | 0167-5273 |
| DOI: | 10.1016/0167-5273(94)02247-g |
| Popis: | The effects of amiodarone (0-100 microM) on the physical state of synthetic and native membranes were investigated by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), probing the bilayer core, and of its anionic propionic acid derivative (DPH-PA), probing the outer regions of the bilayer. In the gel phase of dimyristoylphosphatidylcholine (DMPC) bilayers, amiodarone broadens the transition profile and shifts the phase transition midpoint to lower temperature values, as evaluated by both probes. On the other hand, the drug orders the fluid phase of the lipid either in hydrophobic core or in the outer regions of the bilayer, as detected by DPH and DPH-PA, respectively. The effects of amiodarone on the thermotropic behaviour of DPPC confirm and extend data in DMPC. Cholesterol concentration modulates to a great extent the effects of amiodarone in the fluid phase of DMPC. Thus, both probes, DPH and DPH-PA, detect either ordering effects of amiodarone for low cholesterol concentrations (or = 20 mol%) or disordering amiodarone effects at higher cholesterol levels (20 mol%). In agreement with the results in models of synthetic lipids, the ordering effects of amiodarone in fluid native membranes of mitochondria and brain microsomes are depressed with the increase in intrinsic cholesterol. The ordering effects in mitochondria may induce bioenergetic dysfunctions and consequently disturbances in the electromechanic functioning of myocardium. |
| Databáze: | OpenAIRE |
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