Nissl body

Source: Wikipedia, the free encyclopedia.
microns
(0.03mm).
Drawing of a motor neuron from the ventral horn of the medulla spinals of a rabbit. The angular and spindle-shaped Nissl bodies in the cytoplasm are well shown.

In

ergastoplasm, basophilic bodies,[1] or chromophilic substance.[4] While these organelles differ in some ways from Nissl bodies in neurons,[5] large amounts of rough endoplasmic reticulum are generally linked to the copious production of proteins.[1]

Staining

"Nissl stains" refers to various basic dyes that selectively label negatively charged molecules such as DNA and RNA. Because ribosomes are rich in ribosomal RNA, they are strongly basophilic ("base-loving"). The dense accumulation of membrane-bound and free ribosomes in Nissl bodies results in their intense coloration by Nissl stains, allowing them to be seen with a light microscope.[1]

Size and distribution

Nissl bodies occur in the

motor neurons of the spinal cord and brainstem, where they appear as large, blocky assemblies.[5] In other neurons, they may be smaller, and in some (such as the granule neurons of the cerebellar cortex) very little rough endoplasmic reticulum is present.[5] The pattern of coloration with Nissl stains once was used to classify neurons.[5] For various reasons, this practice has largely ceased, but specific neuronal types do manifest characteristic types of Nissl bodies.[5]

Functional role

The functions of Nissl bodies are thought to be the same as those of the rough endoplasmic reticulum in general, primarily the synthesis and segregation of proteins.[1][2] Similar to the ergastoplasm of glandular cells, Nissl bodies are the main site of protein synthesis in the neuronal cytoplasm.[5] The ultrastructure of Nissl bodies suggests they are primarily concerned with the synthesis of proteins for intracellular use.[7]

Pathology

Nissl bodies show changes under various physiological conditions and in

pathological conditions such as axonotmesis, during which they may dissolve and largely disappear (chromatolysis). If the neuron is successful in repairing the damage, the Nissl bodies gradually reappear and return to their characteristic distribution within the cell.[5]

References

  1. ^
    ISBN 0-8385-0567-8
    .
  2. ^
    ISBN 978-0-7167-3226-6
    . Retrieved 4 January 2013.
  3. PMC 6753910
    .
  4. ISBN 0-7216-3585-7
    .
  5. ^
    ISBN 0-19-506571-9
    .
  6. ISBN 978-3-13-562404-4
    . Retrieved 4 January 2013.
  7. ISBN 978-1-4020-1892-3
    . Retrieved 4 January 2013.

External links
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