The response of neonatal rat locus coeruleus neurons to contact with myelin extracts prepared from the CNS and PNS was examined. The growth cones of these neurons collapsed following contact with central myelin, but continued to elongate on contact with peripheral myelin. Central myelin elicited an increase in the intracellular free calcium concentration in these growth cones, while peripheral ...

Before the advent of critical isotope-labelling experiments (Eichberg & Dawson, 1965), myelin was believed to be metabolically inert. Evidence soon accumulated which indicated that not only did an active myelin metabolism persist in young adult animals, but was accompanied by a progressive change in chemical composition of the sheath. Typically the myelin isolated by centrifugation from develop...

In vitro assays reveal that myelin and oligodendrocytes of the Xenopus spinal cord (SC) are--unlike corresponding components of the optic nerve/tectum (OT)--nonpermissive substrates for regenerating retinal axons. The number of growth cones that crossed SC oligodendrocytes is low but increases significantly (four- to fivefold) in the presence of the antibody IN-1, in which case their numbers ar...

The old concept of myelin as a metabolically inert membrane has been considerably revised as a result of the discovery of numerous enzyme activities in the isolated membrane. The high degree of purification and low levels of contamination markers leave little doubt that the measured activities are intrinsic to myelin itself. Slightly more than half of the discovered activities involve lipid met...

Introduction Myelin water imaging has been successfully used to assess myelin content in human and animal CNS tissue [1,2]. It has been shown that myelin water fraction (MWF) [3] correlates well with the amount of myelin in a rat model of spinal cord injury (SCI) [2] and can therefore be an important marker of the cord pathology. Quantitative T2 measurements used in myelin water imaging require...

PURPOSE: The myelin g-ratio, defined as the ratio between the inner and the outer diameter of the myelin sheath, is a fundamental property of white matter that can be computed from a simple formula (Fig. 1) relating the myelin volume fraction (MVF) to the fiber volume fraction (FVF) or the axon volume fraction (AVF). Recent studies have suggested that the sexual dimorphism in white matter devel...

The vertebrate nervous system is characterized by ensheathment of axons with myelin, a multilamellar membrane greatly enriched in the galactolipid galactocerebroside (GalC) and its sulfated derivative sulfatide. We have generated mice lacking the enzyme UDP-galactose:ceramide galactosyltransferase (CGT), which is required for GalC synthesis. CGT-deficient mice do not synthesize GalC or sulfatid...

Rapid conduction of nerve impulses requires coating of axons by myelin sheaths, which are multilamellar, lipid-rich membranes produced by oligodendrocytes in the central nervous system. To act as an insulator, myelin has to form a stable and firm membrane structure. In this study, we have analyzed the biophysical properties of myelin membranes prepared from wild-type mice and from mouse mutants...

The myelin and lymphocyte protein (MAL) is a tetraspan raft-associated proteolipid predominantly expressed by oligodendrocytes and Schwann cells. We show that genetic ablation of mal resulted in cytoplasmic inclusions within compact myelin, paranodal loops that are everted away from the axon, and disorganized transverse bands at the paranode--axon interface in the adult central nervous system. ...