Abstract

The nodes of Ranvier are critical, unmyelinated gaps in the axonal membrane that facilitate the rapid, saltatory conduction of action potentials in myelinated nerve fibers. While their role in electrophysiology is well-established, the dynamic morphophysiological processes occurring at these nodes in **living** fibers remain a subject of ongoing investigation. This study employs a combination of intravital microscopy and electrophysiological techniques, including voltage clamp experiments, to examine the structural and functional integrity of Ranvier nodes under various osmotic and chemical conditions. Our objective was to move beyond the limitations of fixed histological preparations and investigate the real-time dynamics of the nodal and paranodal regions. Key findings reveal that the structural alterations in the node, such as changes in the cone-shaped myelinated regions and the nodal gap, are not solely dependent on external osmotic changes but are significantly influenced by nonspecific physical alterations in the conformation of axoplasmic proteins. Furthermore, these structural changes correlate directly with measurable electrophysiological changes in sodium, potassium, and leakage conductance. The results suggest a novel form of metabolic transmembrane neuron-glial exchange and emphasize that the physiological state of the node is highly sensitive to the conformational stability of internal axoplasmic components, providing a deeper understanding of nerve impulse propagation and pathology.