Neurofibril

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Related to neurofibrillary: neurofibrillary degeneration, Neurofibrillary tangles

neurofibril

[¦nu̇r·ō′fī·brəl]
(neuroscience)
A fibril of a neuron, usually extending from the processes and traversing the cell body.

Neurofibril

 

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 ?
The variant cells also contained the neurofibrillary tangles that choke the inside of nerve cells causing cell death.
PKC Isozymes Regulate Amyloid Plaque and Neurofibrillary Tangle Metabolism
The major three pathological features, namely the extracellular deposition of the amyloid [beta] protein (A[beta]), the formation of intraneuronal neurofibrillary tangles (NFTs) and selective neuronal loss are predominantly observed in AD neurodegeneration (1,2).
There was also an absence of a central neurofibrillary matrix.
These lesions, called neurofibrillary tangles and senile (amyloid) plaques (often referred to simply as plaques), destroy parts of the brain.
From pathologic reviews in human brain, hallmarks of AD include extracellular plaques and intracellular neurofibrillary tangles (breakdown of cytoskeleton) in parts of the brain involved with cognition and memory.
Scientists noted the extent of different kinds of amyloid plaques, which occur when snipped fragments of a larger protein clump together, and neurofibrillary tangles, which form when threads of the protein tau become entangled, damaging critical neurons, or nerve cells, in the brain.
CSF levels of Tau, a potentially neurotoxic protein making up the neurofibrillary "tangles" that are hallmarks of AD, showed a marked and persistent decline.
Neurofibrillary tangles are the second hallmark of Alzheimer's.
Patients with Down syndrome (DS) who live beyond middle age invariably develop cerebral amyloid (A[Beta]) plaques and neurofibrillary tangles (NFTs), the characteristic lesions of Alzheimer disease (AD).
At death, those with mild cognitive impairment also were much more likely than subjects with no such impairment to have the neuritic plaques, diffuse plaques, and neurofibrillary tangles characteristic of Alzheimer's disease.