The actions of grayanotoxin I, veratrine, and tetrodotoxin on the membrane potential of the Schwann cell were studied in the giant nerve fiber of the squid Sepioteuthis sepioidea. Schwann cells of intact nerve fibers and Schwann cells attached to axons cut lengthwise over several millimeters were utilized. The axon membrane potential in the intact nerve fibers was also monitored. The effects of...

In the preceding paper (Salzer et al ., 1980, J. Cell Biol. 84:753-766), evidence was presented that a neurite membrane fraction could be used to stimulate Schwann cell proliferation in culture . In this study, we present evidence that the mitogenic signal by which intact neurites or neurite membranes stimulate Schwann cell proliferation is located at the neurite surface . This conclusion is ba...

This work investigates the role of galactocerebroside (GalC) in peripheral myelin formation. A monoclonal antibody against GalC was introduced into a myelinating culture system consisting of rat sensory neurons and Schwann cells, without other cell types. At levels that saturated Schwann cell surface GalC, anti-GalC IgG prevented by more than 99% the appearance of myelin sheaths. Ensheathment a...

During development, neuregulin-1 promotes Schwann cell proliferation and survival; its role in later events of Schwann cell differentiation, including myelination, is poorly understood. Accordingly, we have examined the effects of neuregulin-1 on myelination in neuron-Schwann cell cocultures. Glial growth factor (GGF), a neuregulin-1 isoform, significantly inhibited myelination by preventing ax...

This study examined Schwann cell behavior during paranodal demyelination induced by beta,beta'-iminodipropionitrile (IDPN). The stimuli for Schwann cell proliferation, extensively studied in vitro, are less well understood in vivo. Most in vivo systems previously used to examine Schwann cell proliferation in disease are dominated by loss of internodal myelin sheaths. As used in this study, IDPN...

In the preceding paper (Salzer et al., 1980, J. Cell Biol. 84:753--766), evidence was presented that a neurite membrane fraction could be used to stimulate Schwann cell proliferation in culture. In this study, we present evidence that the mitogenic signal by which intact neurites or neurite membranes stimulate Schwann cell proliferation is located at the neurite surface. This conclusion is base...

Neuroblastomas are biologically heterogeneous tumors that consist of two main cell populations: neuroblastic/ganglionic cells and Schwann cells. The amount of Schwannian stroma strongly impacts prognosis, and favorable outcome is associated with tumors that are Schwannian stroma rich/stroma dominant. At the present time, there is controversy regarding the origin of Schwann cells in neuroblastom...

Schwann cells are a regenerative cell type. Following nerve injury, a differentiated myelinating Schwann cell can dedifferentiate and regain the potential to proliferate. These cells then redifferentiate during the repair process. This behaviour is important for successful axonal repair, but the signalling pathways mediating the switch between the two differentiation states remain unclear. Sust...

Schwann cell-axon interactions in the development, maintenance, and regeneration of the normal peripheral nervous system are complex. A previously described transgene-induced insertional mutation (BPFD#36), now referred to as Enervated (Enr), results in disrupted Schwann cell-axon interactions. In this report, after a crush or transection injury to Enr peripheral nerves, we demonstrate impaired...

Little is known about the cytoarchitecture of growth fronts in developing mammalian nerves. We report here the first quantitative, ultrastructural analysis of growth cones (GCs) and their immediate cellular and tissue environment at tips of growing nerves that are nearing their targets in fore limbs of E14 rat embryos. Schwann cell precursor (SCP) marker, p75 neurotrophin receptor, and growth c...