Fañanas cells (also known as Feathered cells of Fañanas) are

glial cell Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. They maintain homeostasis, form myel ...

s of the

cerebellar cortex The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebe ...

. They are located in the granular layer with their cytoplasmatic protrusions extending into the lower part of the molecular layer as well. They are meant to be closely related to and sometimes even called Golgi epithelial cells and are juxtaposed to the

Radial glial cell Radial glial cells, or radial glial progenitor cells (RGPs), are bipolar-shaped progenitor cells that are responsible for producing all of the neurons in the cerebral cortex. RGPs also produce certain lineages of glia, including astrocytes and ...

s or Bergmann glial cells. Fañanas cells are sometimes defined as "specialised astrocytes". The feathered cells are named after Jorge Ramón y Cajal Fañanás, a son of

Santiago Ramón y Cajal Santiago Ramón y Cajal (; 1 May 1852 – 17 October 1934) was a Spanish neuroscientist, pathologist, and histologist specializing in neuroanatomy and the central nervous system. He and Camillo Golgi received the Nobel Prize in Physiology or Me ...

, who first described this type of glial cell in 1916.

Histology

Microscopic studies show that the Fañanas cell represents a satellite glial cell whose protrusions do not contain glial filaments like GFAP. They are located near the

somata The soma (pl. ''somata'' or ''somas''), perikaryon (pl. ''perikarya''), neurocyton, or cell body is the bulbous, non-process portion of a neuron or other brain cell type, containing the cell nucleus. The word 'soma' comes from the Greek '' σῶ� ...

Purkinje cell Purkinje cells, or Purkinje neurons, are a class of GABAergic inhibitory neurons located in the cerebellum. They are named after their discoverer, Czech anatomist Jan Evangelista Purkyně, who characterized the cells in 1839. Structure T ...

s in the granular layer. With regard to the typical "feathered" microscopic structure of the cells, Fañanas glial cells occur in subforms with one, two or multiple "feathers" of cytoplasmatic extensions, that are studded with small, rounded sprouts. The protrusions are often much shorter than those of other Golgi epithelial cells and run parallel to the fibres of the Bergmann glial cells. Fañanas cell extensions are normally not part of the glial limiting membrane. With the Nissl-method, Fañanas cells can be identified by their slightly bigger, roundish and ovally shaped nuclei, scattered in the molecular and granular layer. The cells need to be prepared with a gold sublimate impregnation by Ramón y Cajal or a silver staining method.

Function and clinical relevance

The role of the Fañanas cell in the connectivity and structure of the cerebellar cortex is still unknown. One study found deviations of the expression of

Vimentin Vimentin is a structural protein that in humans is encoded by the ''VIM'' gene. Its name comes from the Latin ''vimentum'' which refers to an array of flexible rods. Vimentin is a type III intermediate filament (IF) protein that is expresse ...

in patients with Creutzfeldt-Jakob disease (CJD) that could be related to pathological changes in Fañanas glia. These variances were also described in cerebellar microglia and Bergmann cells. However, the results of the study did not point at significant mutations in Fañanas cells but rather described the possible importance of

astrocyte Astrocytes (from Ancient Greek , , "star" + , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of e ...

s in general in the

aetiology Etiology (pronounced ; alternatively: aetiology or ætiology) is the study of causation or origination. The word is derived from the Greek (''aitiología'') "giving a reason for" (, ''aitía'', "cause"); and ('' -logía''). More completely, e ...

of CJD.

References

External links

* http://www.medilexicon.com/dictionary/15596 {{Cerebellum Cerebellum Glial cells