Magnocellular neurosecretory cell

Magnocellular neurosecretory cell

Magnocellular neurosecretory cells are large cells within the supraoptic nucleus and paraventricular nucleus of the hypothalamus. They are also found in smaller numbers in accessory cell groups between these two nuclei, the largest one being the nucleus circularis. There are two types of magnocellular neurosecretory cells, oxytocin-producing cells and vasopressin-producing cells, but a small number can produce both hormones. These cells are neuroendocrine neurons, are electrically excitable, and generate action potentials in response to afferent stimulation.

Magnocellular neurosecretory cells in the rat (where these neurons have been most extensively studied) in general have a single long varicose axon, which projects to the posterior pituitary. Each axon gives rise to about 10,000 neurosecretory terminals and many axon swellings that store very large numbers of hormone-containing vesicles. These vesicles are released from the axon swellings and nerve terminals by exocytosis in response to calcium entry through voltage-gated channels, which occurs when action potentials are propagated down the axons.

The cells typically have two or three long dendrites, which also contain large dilations, and which also contain a very high density of hormone-containing vesicles. Oxytocin and vasopressin can, thus, be released within the brain from these dendrites, as well as into the blood from the terminals in the posterior pituitary gland. However, the release of oxytocin and vasopressin from dendrites is not consistently accompanied by peripheral secretion, as dendritic release is regulated differently. Dendritic release can be triggered by depolarisation, but can also be triggered by the mobilisation of intracellular calcium stores. The dendrites receive most of the synaptic inputs from afferent neurons that regulate the magnocellular neurons; typically a magnocellular neuron receives about 10,000 synapses from afferent neurons.

See also

  • Parvocellular neurosecretory cell

References


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Magnocellular — can refer to: Magnocellular cell, part of visual system Magnocellular red nucleus Magnocellular neurosecretory cell Magnocellular pathway Magnocellular theory of dyslexia This disambiguation page lists articles associated with the same title. If… …   Wikipedia

  • Magnocellular part — Magnocellular parts, also called M cells, are cells in the brain concerned primarily with visual perception. In particular these cells are responsible for resolving motion and coarse outlines. The cells have large, fast conducting neurons and… …   Wikipedia

  • Magnocellular cell — Not to be confused with Magnocellular neurosecretory cell. This article is about the lateral geniculate nucleus cell. For the part of the red nucleus, see Magnocellular red nucleus. Neuron: Magnocellular cell NeuroLex ID nifext 42 …   Wikipedia

  • List of topics in cell biology — Cell invokes a major branch of theory and research known variously as cell biology, cellular biology or cytology. The study of cell tissues is known as histology. Cell types are often referred to using the suffixes blast, clast, cyte, especially… …   Wikipedia

  • magnocellular — ¦magnōˌ adjective Etymology: Latin magnus large + English o + cellular more at much : being or containing neurons with large cell bodies motion and depth perception processed by the magnocellular visual pathway neurosecretory magnocellular… …   Useful english dictionary

  • List of distinct cell types in the adult human body — There are about 210 distinct human cell types,.[1][2][3] There are between 50 and 75 trillion cells in the human body.[citation needed] Cell types can be classified by their tissue of origin. However, it is possible for some cells to have their… …   Wikipedia

  • Supraoptic nucleus — Infobox Brain Name = PAGENAME |love GraySubject = GrayPage = Caption = Human supraoptic nucleus (SON, dorsolateral and ventromedial components) in this coronal section is indicated by the shaded areas. Dots represent vasopressin (AVP) neurons… …   Wikipedia

  • Paraventricular nucleus of hypothalamus — Infobox Brain Name = PAGENAME Latin = nuclei paraventricularis hypothalami GraySubject = GrayPage = Caption = Human paraventricular nucleus (PVN) in this coronal section is indicated by the shaded area. Dots represent vasopressin (AVP) neurons… …   Wikipedia

  • Pituitary stalk — Infobox Brain Name = PAGENAME Latin = infundibulum neurohypophyseos GraySubject = 189 GrayPage = 813 Caption = Pituitary stalk not labeled, but is the vertical blue portion. Caption2 = IsPartOf = Components = Artery = Vein = BrainInfoType = hier… …   Wikipedia

  • Endocrine system — In physiology, the endocrine system is a system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body. The endocrine system is in contrast to the exocrine system, which secretes its chemicals using …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”