title: Neutron diffraction studies of oral stratum corneum model lipid membranes.
abstract: In this work we have investigated model lipid mixtures simulating a lipid component of oral stratum corneum (OSC). Neutron diffraction experiments on oriented samples have revealed that SM (bovine brain)/dipalmitoylphosphatidylethanolamine/dipalmitoylphosphatidylcholine (DPPE/DPPC) mixtures at molar ratios of 1/2/1 and 1/1/1 are one-phase membranes. The incorporation of low concentrations of ceramide 6 and cholesterol into SM/DPPC/DPPE bilayers does not result in a phase separation, affecting membrane hydration. The model OSC membrane composed of ceramide 6/cholesterol/fatty acids/cholesterol sulfate/SM (bovine brain)/DPPE/DPPC is characterized by coexistence of several lamellar phases, that behave differently during their hydration in water excess. The phase with lamellar repeat distance of about 45 Å is likely a ceramide-rich phase and shows a restricted swelling in water, while another phase with repeat distance of 50 Å swells very quickly on 15 Å and then disappears. Our results indicate that phospholipid-rich and ceramide-rich domains could possibly coexist in the intercellular space of oral epithelium.
authors.affiliation: Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980, Moscow Region, Russia. rny03@nf.jinr.ru
authors.forename: Natalia Yu
authors.initials: NY
authors.lastname: Ryabova
authors.forename: Stanislav G
authors.initials: SG
authors.lastname: Sheverev
authors.forename: Thomas
authors.initials: T
authors.lastname: Hauß
mesh_terms: D000818:Animals; D002417:Cattle; D008563:Membrane Lipids / Q000737:chemistry*; D008567:Membranes, Artificial; D009061:Mouth Mucosa / Q000737:chemistry*; D033363:Neutron Diffraction
chemical_list: D008563:Membrane Lipids; D008567:Membranes, Artificial