The molecular organization of nerve membranes : VI. The separation of axolemma from schwann cell membranes of giant and retinal squid axons by density gradient centrifugation.

Plasma membranes were isolated from two types of squid nerves which have morphologically, different ratios of axolemma/Schwannlemma (A/S). These membranes were studied by means of differential and density gradient centrifugation.Thoroughly dissected giant axons were used as membrane source having low A/S ratio.

The molecular organization of nerve membranes : V. Properties of mono- and bimolecular films formed with lipids isolated from an axolemma-rich preparation from squid retinal axons.

The formation and properties of mono- and bimolecular films of total lipids extracted from an axolemma-rich preparation from retinal axons of the squid are described.The bilayers formed with α-tocopherol showed resistance values of 10(7) Ω cm(2) indicating their low ionic permeability. These membranes were stable for 30 to 60 min and they behave as an ohmic resistance in the range of -120 to +120 mV.

The molecular organization of nerve membranes : IV. The lipid composition of plasma membranes from squid retinal axons.

The lipid content and composition from an axolemma-rich preparation isolated from squid retinal axons was analyzed.The lipids, which accounted for 45.5% of the dry weight of this membrane, were composed of 22% cholesterol, 66.