13C and 31P nuclear magnetic resonance of lipid dispersions from human aorta

Coarse ("multilamellar") and sonicated ("unilamellar") dispersions of lipid constituents of human aorta have been prepared. 31P nuclear magnetic resonance (nmr) spectra of the coarse dispersions show an unusual pattern compared with pure phospholipid bilayers. The reconstituted membrane is suggested to have considerable amounts of nonbilayer phase, possibly in the form of regions of hexagonal phase with a short major axis, or regions of cubic or rhombic phase admixed with the bilayer phase. High resolution 13C nmr spectra of the sonicated dispersions give narrow signals, indicative of lipids in a fluid environment, and are due mostly to cholesteryl esters and triglycerides.