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|Type:||Artigo de periódico|
|Title:||Interaction Between Local Anesthetics And Liposomes Determined By Infrared Spectroscopy [interação De Anestésicos Locais Com Lipossomos Determinada Por Espectroscopia De Infravermelho]|
De Paula E.
|Abstract:||We examined the effect of two local anesthetics (lidocaine and benzocaine) on the structure and dynamics of egg phosphatidylcholine (EPC) membranes at pH 7.4 and 10.5 in order to assess the preferred environment of these local anesthetics within the bilayer. Changes in the organization of small unilamellar vesicles were monitored by Fourier-transform infrared spectroscopy (FTIR), which revealed that the local anesthetics (LA) changed the water-molecule hydrogen-bonding pattern, monitored by effects on the acyl chain, phosphate group and glycerol carbonyl regions of the phospholipids. The effect of increasing the concentration of local anesthetic on these regions of egg phosphatidylcholine revealed that charged lidocaine increases the access of water to the phosphate groups and to carbonyls in the glycerol region of the bilayer, while uncharged lidocaine (pH 10.5) affected mainly the glycerol carbonyls. Benzocaine, on the other hand diminished the access of water molecules to the glycerol carbonyl region. A model is proposed in which charged and uncharged lidocaine binds to the lipids near the phosphate and glycerol regions of the bilayer. For benzocaine, the main locations proposed are in the glycerol region and at the first carbons of the acyl chain. We propose that this preferential positioning, demonstrated here in model phospholipid membranes, also takes place in the nerve axons, where it could modulate the access of the LA molecules to their protein-binding sites in the voltage-gated sodium channel.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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