1. Bioelectrochemistry. 2012 Oct;87:230-5. doi: 10.1016/j.bioelechem.2012.03.001.
Epub 2012 Mar 23.

Interaction of gentamicin polycation with model and cell membranes.

Kovács E, Savopol T, Iordache MM, Săplăcan L, Sobaru I, Istrate C,
Mingeot-Leclercq MP, Moisescu MG.

Carol Davila Medical and Pharmaceutical University, Biophysics and Cellular
Biotechnology Department, Bucharest, Romania.

The interaction of positively-charged antibiotic gentamicin with cell membranes
was studied to determine if any changes in membrane organization were induced by 
the drug. Opossum kidney epithelia (OK) cells were used as models of eukaryotic
cells. Two methods were used: laurdan fluorescence spectroscopy and fluorescence 
anisotropy recordings on 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene 
p-toluenesulfonate (TMA-DPH) labeled cell suspensions. Both methods showed an
altered membrane hydration and fluidity of gentamicin treated cells. Liposomes
prepared from dimyristoyl-phosphatidylcholine (DMPC) mixed with cardiolipin,
which mimics the heterogeneous charge composition of the natural cell membrane,
were used to determine the effect of gentamicin on artificial bilayers. The
membrane lipid packing as revealed by generalized polarization (GP) and
fluorescence anizotropy variation with increasing temperature was studied. It was
found that the generalized polarization of liposomal membranes containing a
negatively charged lipid (cardiolipin) is higher in the presence of gentamicin;
in the membrane of living cell (OK), gentamicin induces, on the contrary, a
decrease of general polarization. Considering the role of membrane organization
in the function of transmembrane channels and receptors, our findings suggest
hypotheses that may explain the permeation of gentamicin through the living cell 
membrane by using these channels.

Copyright © 2012 Elsevier B.V. All rights reserved.

PMID: 22522030  [PubMed - in process]