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β-Endorphin is an endogenous opioid neuropeptide and peptide hormone that is produced in certain neurons within the central nervous system and peripheral nervous system. It is one of five endorphins that are produced in humans, the others of which include α-endorphin, γ-endorphin, α-neoendorphin, and β-neoendorphin.

The amino acid sequence is: Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-Leu-Phe-Lys-Asn-Ala-Ile-Ile-Lys-Asn-Ala-Tyr-Lys-Lys-Gly-Glu (31 amino acids). The first 16 amino acids are identical to α-endorphin. β-Endorphin is considered to be a part of the endogenous opioid and endorphin classes of neuropeptides; all of the established endogenous opioid peptides contain the same N-terminal amino acid sequence, Tyr-Gly-Gly-Phe, followed by either -Met or -Leu.

Function of β-endorphin, along with other endogenous opioids, has been known to be associated with hunger, thrill, pain, maternal care, sexual behavior, and reward cognition. In the broadest sense, β-endorphin is primarily utilized in the body to reduce stress and maintain homeostasis. In behavioral research, studies have shown that β-endorphin is released via volume transmission into the ventricular system in response to a variety of stimuli, and novel stimuli in particular.

Contents

  null hide 

• 1Formation & Structure
• 2Function & Effects
  • 2.1 Pain Management
  • 2.2Exercise
• 3History
• 4References
• 5External links

Formation & Structure[edit | edit source]

β-Endorphin is primarily found in neurons of the hypothalamus, as well as the pituitary gland. It is derived from β-lipotropin, which is produced in the pituitary gland from a larger peptide precursor, proopiomelanocortin (POMC). POMC is cleaved into two neuropeptides, adrenocorticotropic hormone (ACTH) and β-lipotropin. The formation of β-endorphin is then the result of cleavage of the C-terminal region of β-lipotropin, producing a 31 amino acid-long neuropeptide with an alpha-helical secondary structure. However, POMC also gives rise to other peptide hormones, including α- and γ-melanocyte-stimulating hormone (MSH), resulting from intracellular processing by internal enzymes known as prohormone convertases.

A significant factor that differentiates β-endorphin from other endogenous opioids is its high affinity for and lasting effect on μ-opioid receptors. The structure of β-endorphin in part accounts for this through its resistance to proteolytic enzymes, as its secondary structure makes it less vulnerable to degradation. Tyr-1, Gly-2, Gly-3, Gln-11, Thr-12, Pro-13, Leu-13, and Val-15 in the primary amino acid sequence of β-endorphin interact with Thr-69, Leu-76, Pro-297, Tyr-301, Thr-313, Ser-319, His-321, Phe-322, Cys-323, Ala-325, Leu-326 of the μ-opioid receptor in order for binding to occur. 

Function & Effects[edit | edit source]

β-Endorphin is an agonist of the opioid receptors; it preferentially binds to the μ-opioid receptor. Evidence suggests that it serves as a primary endogenous ligand for the μ-opioid receptor, the same receptor to which the chemicals extracted from opium, such as morphine, derive their analgesic properties. β-Endorphin has the highest binding affinity of any endogenous opioid for the μ-opioid receptor. β-Endorphin is a part of a larger network of neuro-peptides that stimulate and regulate different behavioral patterns. The opioid receptors are a class of G-protein coupled receptors, such that when β-endorphin or another opioid binds, a signaling cascade is induced in the cell. Acytelation of the N-terminus of β-endorphin inactivates it by preventing it from binding to the μ-opioid receptor.

The two main methods by which β-endorphin is utilized in the body are peripheral hormonal action and neuroregulation. β-endorphin and other enkephalins often interact with hormonal systems, being released with ACTH to modulate hormonal system functioning. Neuroregulation by β-endorphin is primarily through interfering with the function of another neuropeptide, either by direct or indirect inhibition.

β-endorphin functions primarily in two ways: directly inhibiting release of a neuropeptide in the peripheral nervous system and prompting a signaling cascade that reduces or interferes with the effect of an opposing pathway. This can be illustrated through β-endorphin's function in pain management. Binding of β-endorphin to the μ-opioid receptor primarily results in analgesic effects, while its binding to κ-opioid receptors limits the release of pain signals in nociceptors (pain receptors). Thus, β-endorphin functions both to reduce pain through direct inhibition of pain signal release and start a signaling cascade that results in analgesic effects.

β-Endorphin function is said to be divided into two main categories: local function and global function. Global function of β-endorphin is related to decreasing bodily stress and maintaining homeostasis resulting in pain management, reward effects, and behavioral stability. β-Endorphin in global pathways diffuse to different parts of the body through cerebral spinal fluid in the spinal cord, allowing for β-endorphin release to affect the peripheral nervous system. Localized function of β-endorphin results in release of β-endorphin in different brain regions such as the amygdala or the hypothalamus.  

Pain Management[edit | edit source]

β-Endorphin has been primarily studied for its influence on nociception (i.e., pain perception). β-endorphin modulates pain perception both in the central nervous system and the peripheral nervous system. When pain is perceived, pain receptors (nociceptors) send signals to the dorsal horn of the spinal cord and then up to the hypothalamus through the release of a neuropeptide called substance P.  In the peripheral nervous system, this signal causes the recruitment T-lymphocytes, white blood cells of the immune system, to the area where pain was perceived. T-lymphocytes release β-endorphin in this localized region, allowing it to bind to opioid receptors, causing direct inhibition of substance P. In the central nervous system, Beta endorphin binds to opioid receptors in the dorsal root and inhibits the release of substance P in the spinal cord, reducing the number of excitatory pain signals sent to the brain. The hypothalamus responds to the pain signal by releasing β-endorphin through the periaqueductal grey network, which mainly acts to inhibit the release of GABA, a neurotransmitter which prevents the release of dopamine. Thus, the inhibition of GABA release by β-endorphin allows for a greater release of dopamine, in part contributing to the analgesic effect of β-endorphin. The combination of these pathways reduce pain sensation, allowing for the body stop a pain impulse once it has been sent.

β-Endorphin has approximately 18 to 33 times the analgesic potency of morphine, though its hormonal effect is species dependent.

Exercise[edit | edit source]

Main article: Neurobiological effects of physical exercise § β-Endorphin

β-Endorphin release in response to exercise has been known and studied since at least the 1980s. Studies have demonstrated that serum concentrations of endogenous opioids, in particular β-endorphin and β-lipotropin, increase in response to both acute exercise and training. The release of β-endorphin during exercise is associated with a phenomenon colloquially known in popular culture as a runner's high.

History[edit | edit source]

β-Endorphin was discovered in camel pituitary extracts by C.H. Li and David Chung. The primary structure of β-endorphin was first unknowingly explored 10 years earlier, when Li and colleagues analyzed the sequence of another neuropeptide produced in the pituitary gland, γ-lipotropin. They noticed that the C-terminus region of this neuropeptide was similar to that of some enkephalins, suggesting that it may have a similar function to these neuropeptides. The C-terminal sequence of γ-lipotropin turned out to be the primary sequence of the β-endorphin.

Last Edits

β-Endorphin is an endogenous opioid neuropeptide found in the neurons of both the central and peripheral nervous system. It is one of five endorphins found in humans, the others of which include α-endorphin, γ-endorphin, α-neoendorphin, and β-neoendorphin.

The amino acid sequence is: Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-Leu-Phe-Lys-Asn-Ala-Ile-Ile-Lys-Asn-Ala-Tyr-Lys-Lys-Gly-Glu (31 amino acids). The first 16 amino acids are identical to α-Endorphin. Beta endorphin is considered to be a part of the endogenous opiate or endomorphine class of neuropeptides, defined to contain this specific amino acid sequence: Tyr-Gly-Gly-Phe.

Function of beta endorphin has been known to be associated with hunger, thrill, pain, maternal care, sexual behavior, and reward pathways. In the broadest sense, beta endorphin is primarily utilized in the body to reduce stress and maintain homeostasis. In behavioral research, studies have shown that beta endorphin is primarily released in response to novel stimuli.

Contents

  null hide 

• 1Formation
• 2Function
• 3History
• 4Effects
  • 4.1Exercise
• 5References
• 6External links

Formation & Structure

Beta endorphin is derived from beta-lipotropin, produced in the pituitary gland from a larger peptide precursor, proopiomelanocortin (POMC). Beta-Endorphin is a peptide, 31 amino acids long, resulting from processing of the precursor proopiomelanocortin (POMC). (Note, POMC also gives rise to other peptide hormones, including adrenocorticotropic hormone (ACTH), as well α- and γ-melanocyte-stimulating hormone (MSH), resulting from intracellular processing by internal enzymes known as prohormone convertases.) POMC is cleaved into two neuropeptides, ACTH and beta-lipotropin. The formation of Beta endorphin is then the result of cleavage of the C terminal region of beta lipotropin, producing a 31 amino acid long neuropeptide.

Differentiating beta endorphin from other endogenous opioids is its high affinity and therefore lasting effect on mu opioid receptors. The structure of beta endorphin in part accounts for this through its resistance to proteolytic enzymes, as its secondary structure makes it less vulnerable to degradation. Tyr 1, Gly 2, Gly 3, Gln 11, Thr 12, Pro 13, Leu 13, and Val 15 on the beta endorphin primary sequence interact with Thr 69, Leu 76, Pro 297, Tyr 301, Thr 313, Ser 319, His 321, Phe 322, Cys 323, Ala 325, Leu 326 of the mu opioid receptor in order for binding to occur. Acytelation of the N terminus of beta endorphin inactivates the endorphin, not allowing it to bind to the mu opioid receptor.

β-Endorphin is found in neurons of the hypothalamus, as well as the pituitary gland.

Function & Effects[edit]

β-Endorphin is derived from β-lipotropin, which is produced in the pituitary gland from a larger peptide precursor, proopiomelanocortin (POMC). POMC is cleaved into two neuropeptides, adrenocorticotropic hormone (ACTH) and β-lipotropin. The formation of β-endorphin is then the result of cleavage of the C-terminal region of β-lipotropin, producing a 31 amino acid-long neuropeptide with an alpha-helical secondary structure. The newly cleaved 31 amino acids are then processed by enzymes in order to produce β-endorphin. However, POMC also gives rise to other peptide hormones, including α- and γ-melanocyte-stimulating hormone (MSH), resulting from intracellular processing by internal enzymes known as prohormone convertases.

A significant factor that differentiates β-endorphin from other endogenous opioids is its high affinity for and lasting effect on μ-opioid receptors. The structure of β-endorphin in part accounts for this through its resistance to proteolytic enzymes, as its secondary structure makes it less vulnerable to degradation. Tyr-1, Gly-2, Gly-3, Gln-11, Thr-12, Pro-13, Leu-13, and Val-15 in the primary amino acid sequence of β-endorphin interact with Thr-69, Leu-76, Pro-297, Tyr-301, Thr-313, Ser-319, His-321, Phe-322, Cys-323, Ala-325, Leu-326 of the μ-opioid receptor in order for binding to occur. Acytelation of the N-terminus of β-endorphin inactivates it by preventing it from binding to the μ-opioid receptor.

β-Endorphin is found in neurons of the hypothalamus, as well as the pituitary gland.

Before:

It is an agonist of the opioid receptors, with evidence suggesting it serves as an endogenous ligand of the μ-opioid receptor, the same receptor to which the chemicals extracted from opium, such as morphine, have their analgesic properties (indeed, the μ-opioid receptor was named based on its most renowned ligand, morphine). Beta endorphin has the highest binding affinity of any opioid to the mu-opioid receptor. Beta endorphin is a part of a larger network of neuropeptides stimulate and regulate specific behavioral patterns. There are two main methods by which beta endorphin affects behavior: peripheral hormonal action and neuroregulating interference with another neurotransmitter.

Beta endorphin function is said to be divided into two main categories: local function and global function. Global function of beta endorphin is related to decreasing bodily stress and maintaining homeostasis resulting in pain management, reward effects, and behavioral stability. Beta endorphin in global pathways diffuse to different parts of the body through cerebral spinal fluid in the spinal cord, allowing for beta endorphin release to affect the peripheral nervous system. Localized function of beta endorphin results in release of beta endorphin in different brain regions such as the amygdala or the hypothalamus. Localized release of beta endorphin inhibits changes in behavioral state (i.e. ), ultimately inhibiting the realization of behavioral goals.

Pain Management

β-Endorphin has been primarily studied for its influence on nociception (i.e., pain perception). β-endorphin modulates pain perception both in the central nervous system and the peripheral nervous system. When pain is perceived, pain receptors (nociceptors) send signals to the dorsal horn of the spinal cord and then up to the hypothalamus through the release of a neuropeptide called substance P. This signal causes the recruitment T lymphocytes, white blood cells of the immune system, to the area where pain was perceived. T lymphocytes release β-endorphin in this localized region, allowing it to bind to opioid receptors in the peripheral nervous system, causing direct inhibition of substance P. In the central nervous system, Beta endorphin binds to opioid receptors in the dorsal root and inhibits the release of substance P in the spinal cord, reducing the number of excitatory pain signals sent to the brain. Pain signals are sent to the spinal cord and then up to the hypothalamus through the release of substance P from sensory neurons. In the peripheral nervous system, β-endorphin binds the μ-opioid receptor, directly inhibiting the release of substance P. In the central nervous system, The hypothalamus responds to the pain signal by releasing β-endorphin is also released through the periaqueductal grey network, in response to this signal and which mainly acts to inhibit the release of GABA, a neurotransmitter which prevents the release of dopamine. Thus, the inhibition of GABA release by β-endorphin allows for a greater release of dopamine, in part contributing to the analgesic effect of β-endorphin. The combination of these pathways reduce pain sensation, allowing for the body stop a pain impulse once it has been sent.

β-Endorphin has approximately 18 to 33 times the analgesic potency of morphine, though its hormonal effect is species dependent.

Before

Beta endorphin has been primarily studied for its influence on pain management. Pain signals are sent to the spinal cord and then up to the hypothalamus through the release of substance P from sensory neurons. In the peripheral nervous system (PNS) beta endorphin binds the mu opioid receptor and inhibits the release of substance P. In the central nervous system, beta endorphin is released through the periaqueductal grey network in response to this signal and mainly acts to inhibit the release of GABA B, a neurotransmitter which prevents the release of dopamine. Thus, the inhibition of GABA B release by beta endorphin allows for a greater release of dopamine. This two fold approach reduces pain sensation, allowing for the body stop a pain impulse once it has been sent.

It is used as an analgesic in the body to numb or dull pains. That is the reason why humans start to feel better immediately after an acute physical trauma even though the symptoms are still present. The reason the pain dulls is because it binds to and activates opioid receptors. β-Endorphin has approximately 18 to 33 times the analgesic potency of morphine, though its hormonal effect is species dependent.

Exercise[edit]

Main article: Neurobiological effects of physical exercise § β-Endorphin

β-Endorphin release in response to exercise has been known and studied since at least the 1980s. Studies have demonstrated that serum concentrations of endogenous opioids, in particular β-endorphin and β-lipotrophin, increase in response to both acute exercise and training. The release of β-endorphin during exercise is associated with a phenomenon colloquially known in popular culture as a runner's high.

History[edit]

β-Endorphin was discovered in camel pituitary extracts by C.H. Li and David Chung. The primary structure of β-endorphin was first unknowingly explored 10 years earlier, when Li and colleagues analyzed the sequence of another neuropeptide produced in the pituitary gland, γ-lipotropin. He noticed that the c-terminus region of this neuropeptide was similar to that of some enkaphalines, suggesting that it may have a similar function to these neuropeptides. This C terminal sequence of γ-lipotropin turned out to be the primary sequence of the β-endorphin. 

Effects[edit]

It is used as an analgesic in the body to numb or dull pains. That is the reason why humans start to feel better immediately after an acute physical trauma even though the symptoms are still present. The reason the pain dulls is because it binds to and activates opioid receptors. β-Endorphin has approximately 18 to 33 times the analgesic potency of morphine, though its hormonal effect is species dependent.

Topic: Beta Endorphin

I plan to add more information regarding the structure and function of the beta endorphin. The beta endorphin, binds to opioid receptors, and is generated when the body experiences hunger, thrill, strenuous physical activity, or feelings of pain. Beta endorphin can bind to 3 different types of opioid receptors (mu, gamma, and kappa opioid receptors), but has the highest affinity for mu receptors, accounting for its function in pain relief. From a behavioral perspective, the beta endorphin generally allows for a state of ease in the body, through volume transmission, allowing for an organism to respond to different environmental stimuli. In the CNS, the beta endorphin creates this at ease affect by up-regulating the release of dopamine in the brain. When beta endorphin binds to the mu opioid receptor, it does not allow for the neuropeptide GABA B to be released. GABA B inhibits dopamine release, and so therefore a reduction in GABA B neuropeptide produces an increase in dopamine release.

Higher amounts of beta endorphin have also been observed in swimmers and runners, suggesting that intense exercise may release more beta endorphin in the body.