Chromaffin cell

Source: Wikipedia, the free encyclopedia.
Medullary chromaffin cell
Adrenal gland. (Medulla labeled at bottom right.)
Details
LocationMedulla adrenal gland
Identifiers
Latinendocrinocytus medullaris
MeSHD019439
THH3.08.02.6.00015
FMA69263
Anatomical terms of microanatomy

Chromaffin cells, also called pheochromocytes (or phaeochromocytes), are

paracrine
signals. Hence they are called neuroendocrine cells.

Structure

There are two types of cells that originate from the neural crest and are related to the sympathetic nervous system (originate from a cell called sympathogonia):[2]

1) Neuroblasts: These cells migrate, during the fourth to the fifth week of fetal development in humans, on both sides of the spinal cord toward the region just behind the dorsal aorta forming the two chains of sympathetic ganglia (Sympathetic chain). From these ganglia, the post synaptic sympathetic fibers will arise and extend toward their target organ. Some of these cells will migrate to the adrenal medulla to form sympathetic ganglia cells within the adrenal medulla (without postsynaptic sympathetic fibers). A tumor arising from these cells is called neuroblastoma.[3]

2) Chromaffin cells (or pheochromocytes): These cells will migrate to the area adjacent to the sympathetic ganglia (hence the name paraganglia) and to the adrenal medulla where they will be the most abundant type of cells. The largest extra-adrenal cluster of chromaffin cells in mammals is the organ of Zuckerkandl.[4] Tumors arising from these cell are called paragangliomas or pheochromocytomas. These terms can be used interchangeably but usually paraganglioma refer to a tumor originating from chromaffin cells outside the adrenal gland, which can also be called extra-adrenal pheochromocytoma, whereas pheochromocytoma typically refer to a tumor originating from the chromaffin cells within the adrenal gland.[2]

Chromaffin cells also settle near the

carotid arteries. In lower concentrations, extra-adrenal chromaffin cells also reside in the bladder wall, prostate, and behind the liver
.

In non-mammals, chromaffin cells are found in a variety of places, generally not organised as an individual organ, and may be without innervation, relying only on

paracrine signals for secretion.[5][6]

Function

Epinephrine
)
Noradrenaline (Norepinephrine)

Chromaffin cells of the adrenal medulla are innervated by the

endorphins (which are secreted from the pituitary); all of these peptides bind to opioid receptors and produce analgesic (and other) responses. The hormones are secreted from chromaffin granules; this is where the enzyme dopamine β-hydroxylase catalyses the conversion of dopamine to noradrenaline.[7] Distinct N and E cell forms exist (also Na and A cells in British nomenclature - noradrenaline and adrenaline); the former produce norepinephrine, the latter arise out of N cells through interaction with glucocorticoids, and convert norepinephrine into epinephrine.[8]

Catecholamine biosynthesis
Catecholamine biosynthesis

Clinical significance

Neoplasms arising from these cells are pheochromocytomas (also called chromaffin or sympathetic paragangliomas, in contrast to non-chromaffin or parasympathetic paragangliomas of glomus cells). Sometimes only neoplasms of adrenal origin are named pheochromocytomas, while others are named extra-adrenal paragangliomas.

Heart failure

Following

GRK2) which effectively eliminates the normal autocrine-type negative feedback that normally prevents the cells from over producing the catecholamines and replaces it with a positive feedback loop in which increased secretion further elicits more secretion.[9] This upregulation of GRK2 is also accompanied by upregulation and increased production of the enzyme tyrosine hydroxylase, which catalyzes the rate limiting step of catecholamine synthesis.[10]

History

The word "chromaffin" comes from a portmanteau of chromium and affinity. They are named as such because they can be visualised by

catecholamines
to form a brown color, most strongly in the cells secreting noradrenaline. Chromaffin cells are also called pheochromocytes.

The

enterochromaffin cells
are so named because of their histological similarity to chromaffin cells (they stain yellow when treated with chromium salts), but their function is quite different and they are not derivatives of the neural crest.

Paraganglia are clusters of either chromaffin cells or glomus cells
near sympathetic ganglia.

See also

References

  1. PMID 23078542
    .
  2. ^ a b "Chapter 179. The Paraganglionic System: The Paraganglia - Review of Medical Embryology Book - LifeMap Discovery". discovery.lifemapsc.com. Archived from the original on 2016-12-20. Retrieved 2017-06-03.
  3. ^ "Chapter 164. The Autonomic Nervous System: The Sympathetic System - Review of Medical Embryology Book - LifeMap Discovery". discovery.lifemapsc.com. Archived from the original on 2017-05-05. Retrieved 2017-06-03.
  4. PMID 23078542
    .
  5. S2CID 42402600
    .
  6. PMID 4941407. Archived from the original
    (PDF) on 2016-03-05. Retrieved 2013-03-01.
  7. PMID 11315316. Archived from the original
    (PDF) on 2017-08-09. Retrieved 2013-02-25.
  8. ISBN 978-0-443-06850-8
    .
  9. PMID 26849467
    .
  10. PMID 20351116
    .

External links

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