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A fibril of a neuron, usually extending from the processes and traversing the cell body.



a microscopic filament that is found upon treatment of nerve cells—neurons—and the longest outgrowths of the nerve cells—axons—with silver salts and other reagents.

In the late 19th and early 20th centuries, neurofibrils were ascribed the function of conducting nerve impulses. This view proved to be erroneous when it was found that nerve impulses are conducted by the external membrane of the neuron. Electron microscopy revealed two kinds of longitudinal neurofibrils in the outgrowths of neurons: neurotubules and neurofilaments. Neurotubules are from 20 to 25 nm in diameter and are formed from the protein tubulin; they are believed to transport substances along the axon. The threadlike neurofilaments are formed from a protein similar to the muscle protein actin. Neurofilaments are especially numerous in the movable terminal portions of growing axons.

References in periodicals archive ?
El estudio histopatologico evidencio proliferacion glial con fondo neurofibrilar que alterna con celulas oligodendrogliales y microquistes, compatible con tumor disembrioplasico neuroepitelial.
En la patogenesis se ha identificado una hiperfosforilacion anormal de las proteinas tau que es responsable de la degeneracion neurofibrilar, pero la causa primaria de estas taupatias es aun incierta, por lo que se han postulado otras causas, como acumulacion dietaria de neurotoxinas o eventos postinfecciosos (5).
36) Se discute la importancia relativa de factores tales como la formacion del amiloide, la degeneracion neurofibrilar, los fenomenos inflamatorios y los radicales libres, alteraciones en la glia, mecanismos inmunologicos, y otros.