Local anesthetics: interaction with human erythrocyte membranes as studied by ¹H and 31P nuclear magnetic resonance

Author(s)

Leonardo Fernandes Fraceto ^[1] ; Eneida de Paula ^[2]

Affiliation

^[1] Universidade Estadual de Campinas. Instituto de Biologia. Departamento de Bioquímica

^[2] Universidade Estadual de Campinas. Instituto de Biologia. Departamento de Bioquímica

• Document type: Journal article
• Source: Química Nova; v. 27, n. 1, p. 66-71, 2004-02-00.

Abstract

The literature carries many theories about the mechanism of action of local anesthetics (LA). We can highlight those focusing the direct effect of LA on the sodium channel protein and the ones that consider the interaction of anesthetic molecules with the lipid membrane phase. The interaction between local anesthetics and human erythrocyte membranes has been studied by ¹H and 31P nuclear magnetic resonance spectroscopy. It was found that lidocaine (LDC) and benzocaine (BZC) bind to the membranes, increase the mobility of the protons of the phospholipid's acyl chains, and decrease the mobility and/or change the structure of the polar head groups. The results indicate that lidocaine molecules are inserted across the polar and liquid interface of the membrane, establishing both electrostatic (charged form) and hydrophobic (neutral form) interactions. Benzocaine locates itself a little deeper in the bilayer, between the interfacial glycerol region and the hydrophobic core. These changes in mobility or conformation of membrane lipids could affect the Na+-channel protein insertion in the bilayer, stabilizing it in the inactivated state, thus causing anesthesia. (AU)

• FAPESP's process: 96/01451-9 - Local Anesthetics: Synthesis, Structural and Physico-Chemical Properties, and Interaction with Model and Biological Membranes
• Grantee: Shirley Schreier
• Support Opportunities: Research Projects - Thematic Grants