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All parts of the brain › Brain chemicals › Endorphins

Where are endorphins made in the brain?

Endorphins are made by POMC neurons of the arcuate nucleus in the hypothalamus and by the pituitary gland below it; the main one, beta-endorphin, acts on the periaqueductal grey of the midbrain and in the spinal cord to damp pain signals. [1][2][3][4]

The 3D brain needs JavaScript. The lists below still say where endorphins are made and where they are sent.

Lit: the parts that hold the cells making endorphins (blue) and the parts they are sent to (orange).

Slice

Where endorphins are made is lit in blue, where they are sent in orange. Drag to turn, pinch or scroll to zoom; tap a part or a “light” button to name it on its own; .

The pituitary makes it (β-endorphin) mostly in its anterior lobe and releases it into the blood. In the brain the hypothalamus releases beta-endorphin through the periaqueductal grey, the centre that turns pain down from above, and in the spinal cord it cuts the release of substance P, a messenger that carries pain signals in. [1][2][3][4]

Not separate shapes in this atlas; lit: the parts that hold them. Lit in blue: the whole hypothalamus and pituitary gland, which hold the arcuate nucleus and POMC-making cells of its anterior and intermediate lobes; the cell groups that make endorphins are too small to be shapes in the BodyParts3D model, so nothing is drawn at a guessed point. [2][3][1][4]

Lit in orange: the midbrain, cerebral aqueduct, spinal cord (central canal) and amygdala, where the cited sources say beta-endorphin acts or is released. The fibres themselves are not drawn: the two colours show where the cells are and where they send endorphins, not the routes in between. [5]

Made in: lit in blue

  • Arcuate nucleus, lit as the hypothalamus: Its POMC neurons, at the base of the hypothalamus beside the third ventricle, make the precursor protein POMC, which is cut into beta-endorphin and other signals; these are the hypothalamic beta-endorphin neurons. The nucleus has no shape of its own here, so the whole hypothalamus is lit. [2][3][1]
  • Pituitary gland, lit as the pituitary gland: POMC is made mainly by the corticotroph cells of the anterior lobe, and also by the melanotroph cells of the intermediate lobe; beta-endorphin is the main form of endorphin in the anterior pituitary. Endorphins are stored here and released into the blood. [3][1][4]

Sent to: lit in orange

  • Periaqueductal grey, lit as the midbrain and cerebral aqueduct (hypothalamus → Periaqueductal grey): The hypothalamus answers a pain signal by releasing beta-endorphin through the periaqueductal grey network. The PAG, the grey matter around the cerebral aqueduct, is the main control centre for the brain’s descending modulation of pain; it is not a separate shape here, so the midbrain and the aqueduct are lit. [1][6]
  • Spinal cord (down to the spinal cord): Beta-endorphin acts in the spinal cord to cut the release of substance P, the messenger pain-sensing nerves use there, so less of the signal is passed up to the brain. This atlas draws the cord only as its central canal, cropped just below the medulla, so that thin line is what is lit. [1][4]
  • Amygdala (local release): Named, with the hypothalamus itself, as a brain region where beta-endorphin is released locally, as opposed to its wider, brain-wide role. [1]
  • Also reached but inside the part already lit in blue: the arcuate nucleus’s POMC neurons project widely, including to every nucleus of the hypothalamus. [2]
  • Not lit as a target: the blood. The pituitary’s beta-endorphin goes into the circulation, and circulating beta-endorphin does not cross the blood–brain barrier, so blood levels and brain levels are separate pools. [1]

The pathways, as the sources name them

  • Hypothalamus → Periaqueductal grey, from the beta-endorphin neurons of the hypothalamus to the periaqueductal grey of the midbrain. There beta-endorphin mainly holds back the release of GABA, the brain’s main brake; with less GABA, more dopamine is released, which the source counts as part of how pain is damped. [1]
  • Down to the spinal cord, beta-endorphin carried down to the spinal cord, where pain signals from the body come in. In the source’s account its brain-wide action spreads through the cerebrospinal fluid of the spinal cord, where it lowers substance P release and so the excitatory signal sent up to the brain. [1]
  • Local release, beta-endorphin released within single brain regions, such as the amygdala and the hypothalamus. The source sets this local action against the brain-wide one, which serves stress reduction, the body’s steady state, pain and reward. [1] See What part of the brain controls the stress response?

Good to know

  • There are three endorphins, alpha-, beta- and gamma-endorphin; beta-endorphin is a peptide 31 amino acids long. [4][1]
  • All of them are cut from one precursor, POMC (241 amino acids), which can be processed into up to ten active peptides: it is first split into ACTH, the hormone that drives cortisol release, and beta-lipotropin, and beta-endorphin is the tail end of beta-lipotropin. [3][1]
  • In the arcuate nucleus the same POMC cells also release α-MSH, which lowers appetite, and their release of beta-endorphin is regulated by NPY from the neighbouring appetite neurons. [2] See What part of the brain controls hunger?
  • Endorphins play a major role in the body’s inhibitory response to pain, and they are released from the pituitary typically in response to pain. [4]
  • In the broadest sense, beta-endorphin is used by the body to reduce stress and keep a steady internal state (homeostasis). [1] See What part of the brain controls the stress response?
  • Exercise: vigorous aerobic exercise can trigger endorphin production, and a bout of aerobic exercise significantly raises beta-endorphin in the blood. Beta-endorphin has been proposed as a cause of the “runner’s high”, but experiments that block its receptor show endorphins are not strictly needed for exercise euphoria; endocannabinoids are suggested as more likely contributors. Endorphins may partly explain the reduced pain felt after exercise. [4][1]
  • Discovery: peptides of this family were first found in the brain in 1973 at the University of Aberdeen by John Hughes and Hans Kosterlitz; in 1976 Choh Hao Li and David Chung sequenced alpha-, beta- and gamma-endorphin isolated from camel pituitary glands. [4][1]

What it takes part in

Each lit with every part that takes part: What part of the brain controls the stress response? · What part of the brain controls hormones? · What part of the brain controls hunger?

Where they are made, each on its own page: Arcuate nucleus, Pituitary gland.

Sources

  1. Wikipedia: Beta-Endorphin
  2. Wikipedia: Arcuate nucleus (hypothalamus)
  3. Wikipedia: Proopiomelanocortin
  4. Wikipedia: Endorphins
  5. BodyParts3D 4.0 (3D model measured on this page), © DBCLS, CC BY-SA 2.1 Japan
  6. Wikipedia: Periaqueductal gray

Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); the cell groups that make endorphins have no shape in it, so the parts that hold them are lit. Real brains vary.