The Demyelinated Neuron Researchers in Dr. Waxman's laboratory at Yale are studying how to induce functional recovery of demyelinated neurons by investigating the molecular architecture of myelinated neurons. At regularly spaced intervals along the length of a normal myelinated neuron, there are interruptions in the myelin, called the nodes of Ranvier. The membrane of the neuron at the nodes of Ranvier has different characteristics than the membrane under the myelin. In particular, the membrane at the nodes has many channels that allow sodium ions to cross the membrane and few channels that allow the passage of potassium ions. The sodium channels act as batteries, conducting electrical impulses along the length of the neuron.
Potassium channels act as brakes, slowing the conduction.
Demyelina-tion of the nerve exposes membrane that has many potassium channels and few sodium channels, thereby interfering with conduction. Dr. Waxman's laboratory is also investigating why remissions occur in the absence of remyelination of the neuron. Some evidence indicates that the membrane components of the demyelinated neuron reorganize so that the membrane acquires new sodium channels and regains the ability to conduct impulses. The researchers have evidence that two mechanisms might be at work. The first is that the neuron turns on the machinery to produce new sodium channels and then insert them into the membrane.