INVESTIGADORES
GARCIA Daniel Asmed
congresos y reuniones científicas
Título:
Studies of effects of flunitrazepam on the lamellar-hexagonal II phase transition of phosphatidyl-ethanolamine. Use of merocyanine 540 as a fluorescent indicator
Autor/es:
GARCIA DA; PERILLO MA,
Lugar:
Bariloche
Reunión:
Congreso; XXXII Reunión Anual de la Sociedad Argentina de Biofísica; 2003
Resumen:
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Flunitrazepam (FNT)
is an extensively used benzodiazepine (BZD) due to its potent anxiolytic and
hypnotic action. Previous studies of our group demonstrated that BZD-membrane
interaction could be explained by a partition equilibrium model. We showed that
BZD partitioning in the membrane increased in quantity and depth as the
membrane structural order decreased. Moreover, the localization of BZDs at the
phospholipid polar head region could explain the decrease in the size of dpPC
vesicles, through a mechanism that involves the increment in the relative
volume of this polar head region inducing an increase in the vesicles surface
curvature. In the present work we studied if FNT can affect the
lamellar-hexagonal II phase transition of phosphatidyl ethanolamine through a
similar mechanism. This study was approached by using the fluorescent dye
merocyanine 540 which is sensitive to the molecular packing of membrane lipids.
A detailed analysis of the effects of FNT on merocyanine absorption,
fluorescence emission and excitation spectra, was performed. The results
indicated that merocyanine behaved as a good indicator of this phase transition
as was previously described. FNT did not affect the transition temperature but
showed a tendency to diminish the dye fluorescence emission intensity which
could involve topological changes leading to modifications in the polarity of
the region sensed by merocyanine.