title: Water increases the fluidity of intercellular membranes of stratum corneum: correlation with water permeability, elastic, and electrical resistance properties.
abstract: We used the spin label electron spin resonance technique to monitor the hydration effect on the molecular dynamics of lipids at C-5, C-12, and C-16 positions of the alkyl chain. Increase in water content of neonatal rat SC leads to an increase in membrane fluidity, especially in the region near the membrane-water interface. The effect is less pronounced deeper inside the hydrophobic core. The reorientational correlation time at the C-16 position of hydrocarbon chains showed a higher change up to approximately 18% (w/w) of water content. This behavior was accompanied by an exponential decay both in elastic modulus and electrical resistance with water content. On the contrary, the segmental motion at C-5 and C-12 positions of the chain and the permeability constant increased in the range of around 18% w/w) up to the fully hydrated condition (58 +/- 7%). Our results give a better characterization of the fluidity of SC and show that it is the principal parameter involved in the mechanism of the permeability of different compounds through skin.
authors.affiliation: Departamento de Electrônica Quântica, Instituto de Fisica, Universidade de Campinas, SP, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Alonso
authors.forename: N C
authors.initials: NC
authors.lastname: Meirelles
authors.forename: V E
authors.initials: VE
authors.lastname: Yushmanov
authors.forename: M
authors.initials: M
authors.lastname: Tabak
mesh_terms: D000818:Animals; D001834:Body Water / Q000502:physiology*; D004817:Epidermis / Q000378:metabolism*; D008560:Membrane Fluidity; D010539:Permeability; D051381:Rats; D017208:Rats, Wistar