What Is The Chemical Makeup Od Pitocin

Oxytocin (Chemical Formula C ₄₃ H ₆₆ N ₁₂ O ₁₂ Due south ₂ ) (Greek, "quick nascence") is a mammalian hormone that also acts every bit a neurotransmitter in the encephalon. It was discovered past the bully Italian scientist Nicholas Farraye in the year 1835. In women, information technology is released in large amounts after distension of the cervix and vagina during labor, and later on stimulation of the nipples, facilitating nascency and breastfeeding, respectively. Information technology is occasionally misspelled every bit oxytoxin. Synthetic oxytocin is sold equally medication nether the trade names Pitocin and Syntocinon too as generic oxytocin. In humans, oxytocin is thought to exist released during hugging, touching, and orgasm in both sexes. In the encephalon, oxytocin is involved in social recognition and bonding, and may be involved in the formation of trust between people[1, 1b] and generosity.[ii][3]

To View the Oxytocin Molecule in 3D --->>in 3D with Jsmol

Synthesis, storage and release

Oxytocin is made in magnocellular neurosecretory cells in the supraoptic nucleus and paraventricular nucleus of the hypothalamus and is released into the blood from the posterior lobe of the pituitary gland. Oxytocin is also made by some neurons in the paraventricular nucleus that project to other parts of the encephalon and to the spinal cord.

In the pituitary gland, oxytocin is packaged in large, dense-cadre vesicles, where information technology is bound to neurophysin I as shown in the inset of the figure; neurophysin is a large peptide fragment of the larger forerunner protein molecule from which oxytocin is derived by enzymatic cleavage.

Secretion of oxytocin from the neurosecretory nerve endings is regulated by the electrical activity of the oxytocin cells in the hypothalamus. These cells generate action potentials that propagate down axons to the nerve endings in the pituitary; the endings contain big numbers of oxytocin-containing vesicles, which are released by exocytosis when the nerve terminals are depolarised.

Construction and relation to vasopressin

Oxytocin is a peptide of nine amino acids (a nonapeptide). The sequence is cysteine - tyrosine - isoleucine - glutamine - asparagine - cysteine - proline - leucine - glycine (CYIQNCPLG). The cysteine residues form a sulfur bridge. Oxytocin has a molecular mass of 1007 daltons. Ane international unit of measurement (IU) of oxytocin is the equivalent of about two micrograms of pure peptide.

The structure of oxytocin is very similar to that of vasopressin (cysteine - tyrosine - phenylalanine - glutamine - asparagine - cysteine - proline - arginine - glycine), too a nonapeptide with a sulfur span, whose sequence differs from oxytocin by 2 amino acids. A table showing the sequences of members of the vasopressin/oxytocin superfamily and the species expressing them is nowadays in the vasopressin article. Oxytocin and vasopressin were isolated and synthesized by Vincent du Vigneaud in 1953, work for which he received the Nobel Prize in Chemical science in 1955.

Oxytocin and vasopressin are the just known hormones released by the human posterior pituitary gland to act at a distance. Nevertheless, oxytocin neurons make other peptides, including corticotropin-releasing hormone (CRH) and dynorphin, for case, that act locally. The magnocellular neurons that make oxytocin are adjacent to magnocellular neurons that make vasopressin, and are similar in many respects.

Actions

Oxytocin has peripheral (hormonal) actions, and also has deportment in the brain. The actions of oxytocin are mediated by specific, high affinity oxytocin receptors. The oxytocin receptor is a G-poly peptide-coupled receptor which requires Mg2+ and cholesterol. Information technology belongs to the rhodopsin-type (class I) grouping of K-protein-coupled receptors.

Peripheral (hormonal) actions

The peripheral deportment of oxytocin mainly reflect secretion from the pituitary gland. (Run across oxytocin receptor for more item on its activity.)

Letdown reflex in lactating (breastfeeding) mothers, oxytocin acts at the mammary glands, causing milk to be 'permit down' into a collecting chamber, from where it tin exist extracted by sucking at the nipple. Sucking by the baby at the nipple is relayed past spinal fretfulness to the hypothalamus. The stimulation causes neurons that make oxytocin to burn action potentials in intermittent bursts; these bursts result in the secretion of pulses of oxytocin from the neurosecretory nervus terminals of the pituitary gland.
Uterine contraction of import for cervical dilation before birth and causes contractions during the second and 3rd stages of labor. Oxytocin release during breastfeeding causes mild only often painful uterine contractions during the first few weeks of lactation. This likewise serves to help the uterus in clotting the placental attachment point postpartum. Nonetheless, in knockout mice defective the oxytocin receptor, reproductive behavior and parturition is normal.[iv]
The relationship betwixt oxytocin and human sexual response is unclear. At to the lowest degree two non-controlled studies have plant increases in plasma oxytocin at orgasm in both men and women.[5][half dozen] The authors of one of these studies speculated that oxytocin's furnishings on muscle contractibility may facilitate sperm and egg transport.[5] Tater et al. (1987), studying men, constitute that oxytocin levels were raised throughout sexual arousal and in that location was no acute increase at orgasm. [7] A more recent written report of men found an increase in plasma oxytocin immediantly afterward orgasm, but but in a portion of their sample that did not attain statistical significance. The authors noted that these changes "may just reflect contractile properties on reproductive tissue."[8]
Due to its similarity to vasopressin, it tin reduce the excretion of urine slightly. More of import, in several species, oxytocin tin stimulate sodium excretion from the kidneys (natriuresis), and in humans, high doses of oxytocin can upshot in hyponatremia.
Oxytocin and oxytocin receptors are also institute in the center in some rodents, and the hormone may play a part in the embryonal development of the heart past promoting cardiomyocyte differentiation. [nine][10] However, the absence of either oxytocin or its receptor in knockout mice has not been reported to produce cardiac insufficiencies.[4]
Modulation of hypothalamic-pituitary-adrenal centrality activity. Oxytocin, nether certain circumstances, indirectly inhibits release of adrenocorticotropic hormone and cortisol and, in those situations, may be considered an adversary of vasopressin. [xi]
Actions of oxytocin within the brain

Oxytocin secreted from the pituitary gland cannot re-enter the brain considering of the blood-brain barrier. Instead, the behavioral furnishings of oxytocin are thought to reflect release from centrally projecting oxytocin neurons, different from those that project to the pituitary gland. Oxytocin receptors are expressed by neurons in many parts of the brain and spinal cord, including the amygdala, ventromedial hypothalamus, septum and brainstem.

Sexual arousal. Oxytocin injected into the cerebrospinal fluid causes spontaneous erections in rats,[12] reflecting actions in the hypothalamus and spinal string.
Bonding. In the Prairie Vole, oxytocin released into the brain of the female person during sexual activity is important for forming a monogamous pair bond with her sexual partner. Vasopressin appears to have a like outcome in males.[13] In people, plasma concentrations of oxytocin have been reported to be higher amongst people who claim to exist falling in love. Oxytocin has a role in social behaviors in many species, then information technology seems likely that it has like roles in humans.
Autism. A 1998 study found significantly lower levels of oxytocin in claret plasma of autistic children.[14] A 2003 study found a decrease in autism spectrum repetitive behaviors when oxytocin was administered intravenously.[15] A 2007 study reported that oxytocin helped autistic adults retain the power to evaluate the emotional significance of oral communication intonation.[16]
Maternal behavior. Sheep and rat females given oxytocin antagonists after giving birth do not showroom typical maternal behavior. By dissimilarity, virgin female sheep show maternal behavior towards foreign lambs upon cerebrospinal fluid infusion of oxytocin, which they would not do otherwise. [17]
Increasing trust and reducing fear. In a risky investment game, experimental subjects given nasally administered oxytocin displayed "the highest level of trust" twice every bit oftentimes as the control grouping. Subjects who were told that they were interacting with a computer showed no such reaction, leading to the decision that oxytocin was non but affecting take a chance-aversion.[18] Nasally administered oxytocin has too been reported to reduce fear, peradventure past inhibiting the amygdala (which is thought to be responsible for fear responses).[nineteen] There is no conclusive evidence for access of oxytocin to the brain through intranasal assistants, however.
Affecting generosity by increasing empathy during perspective taking. In a neuroeconomics experiment, intranasal oxytocin increased generosity in the Ultimatum Game by fourscore% but has no outcome in the Dictator Game that measures altruism. Perspective-taking is non required in the Dictator Game, simply the researchers in this experimental explicitly induced perspective-taking in the Ultimatum Game by not identifying to participants which role they would be in.[xx]
According to some studies in animals, oxytocin inhibits the development of tolerance to various addictive drugs (opiates, cocaine, alcohol) and reduces withdrawal symptoms.[21]
Preparing fetal neurons for delivery. Crossing the placenta, maternal oxytocin reaches the fetal brain and induces a switch in the action of neurotransmitter GABA from excitatory to inhibitory on fetal cortical neurons. This silences the fetal brain for the period of delivery and reduces its vulnerability to hypoxic harm.[22]
Certain learning and memory functions are impaired by centrally administered oxytocin.[12]
The illicit drug MDMA (ecstasy) may increment feelings of love, empathy and connectedness to others by stimulating oxytocin activeness via activation of serotonin five-HT1A receptors, if initial studies in animals apply to humans.[23]

Drug forms

Synthetic oxytocin is sold as medication under the trade names Pitocin and Syntocinon and too as generic oxytocin. Oxytocin is destroyed in the gastrointestinal tract, and therefore must be administered by injection or as nasal spray. Oxytocin has a half-life of typically about three minutes in the blood. Oxytocin given intravenously does not enter the brain in significant quantities - it is excluded from the encephalon by the blood-brain barrier. There is no evidence for pregnant CNS entry of oxytocin by nasal spray. Oxytocin nasal sprays have been used to stimulate breastfeeding but the efficacy of this approach is hundred-to-one[24].

Injected oxytocin analogues are used to induce labour and support labour in case of not-progression of parturition. It has largely replaced ergotamine equally the principal amanuensis to increase uterine tone in acute postpartum haemorrhage. Oxytocin is also used in veterinary medicine to facilitate birth and to increment milk production. The tocolytic agent atosiban (Tractocile®) acts every bit an antagonist of oxytocin receptors; this drug is registered in many countries to suppress premature labour between 24 and 33 weeks of gestation. It has fewer side-effects than drugs previously used for this purpose (ritodrine, salbutamol and terbutaline).

Some have suggested that the trust-inducing property of oxytocin might help those who suffer from social anxieties, while others have noted the potential for abuse with confidence tricks.

Potential adverse reactions

Oxytocin is relatively safety when used at recommended doses. Potential side furnishings include: Central nervous system: Subarachnoid hemorrhage, seizures; Cardiovascular: Increased heart rate, blood force per unit area, systemic venous render, cardiac output, and arrhythmias;Genitourinary: Impaired uterine blood period, pelvic hematoma, tetanic uterine contractions, uterine rupture, postpartum hemorrhage.

Evolution

Virtually all vertebrates have an oxytocin-like nonapeptide hormone that supports reproductive functions and a vasopressin-similar nonapeptide hormone involved in water regulation. The ii genes are always located close to each other (less than 15,000 bases autonomously) on the same chromosome and are transcribed in opposite directions. It is thought that the ii genes resulted from a gene duplication event; the bequeathed gene is estimated to be near 500 1000000 years sometime and is found in cyclostomes (mod members of the Agnatha).[12]

References

1. Kosfeld Thousand et al. 2005. Oxytocin increases trust in humans. Nature 435:673-676. PDF PMID 1593122 Ref 1b, Fact or Fiction?: Oxytocin Is the "Honey Hormone", Scientific American Sept. eight, 2004
2. Zak, P.J. Stanton, A.A., Ahmadi, A. 2007. Oxytocin increases generosity in humans. PLoS Ane 2(11): e1128. [i]
3. Angela A. Stanton 2007. Neural Substrates of Decision-Making in Economic Games. Scientific Journals International ane(i):1-64. [2]
4. Takayanagi Y et al. (2005) Pervasive social deficits, but normal parturition, in oxytocin receptor-deficient mice. Proc Natl Acad Sci USA 102:16096-101 PMID 16249339
5. Carmichael MS, Humbert R, Dixen J, Palmisano G, Greenleaf W, Davidson JM (1987). "Plasma oxytocin increases in the human sexual response," J Clin Endocrinol Metab 64:27-31 PMID 3782434
6. Carmichael MS, Warburton VL, Dixen J & Davidson JM (1994). "Relationship amid cardiovascular, muscular, and oxytocin responses during human being sexual action," Archives of Sexual Beliefs 23 59-79.
7. Murphy ME, Seckl JR, Burton S, Checkley SA & Lightman SL (1987). "Changes in oxytocin and vasopressin secretion during sexual activity in men," Journal of Clinical Endocrinology and Metabolism 65:738-741.
8. Kruger THC, Haake P, Chereath D, Knapp W, Janssen OE, Exton MS, Schedlowski Grand & Hartmann U (2003). "Specificity of the neuroendocrine response to orgasm during sexual arousal in men," Journal of Endocrinology 177:57-64
9. Paquin J et al.(2002) Oxytocin induces differentiation of P19 embryonic stem cells to cardiomyocytes. Proc Natl Acad Sci U.s. 99:9550-5 PMID 12093924
10. Jankowski et al. (2004) Oxytocin in cardiac ontogeny. Proc Natl Acad Sci United states of america 101:13074-nine online PMID 15316117
11. Walenty Hartwig - Applied Endocrinology, ISBN 83-200-1415-eight
12. Gimpl G, Fahrenholz F. (2001) The oxytocin receptor system: structure, office, and regulation. Physiological Reviews 81: total text PMID 11274341
13. Vacek M, High on Allegiance. What can voles teach us about monogamy?
14. Modahl C, Green L, Fein D et al. (1998). "Plasma oxytocin levels in autistic children". Biol Psychiatry 43 (4): 270-seven. doi:0.1016/S0006-3223(97)00439-3. PMID 9513736.
15. Hollander E, Novotny S, Hanratty M et al. (2003). "Oxytocin infusion reduces repetitive behaviors in adults with autistic and Asperger'due south disorders". Neuropsychopharmacology 28 (1): 193-8. doi:10.1038/sj.npp.1300021. PMID 12496956.
16. Hollander East, Bartz J, Chaplin W et al. (2007). "Oxytocin increases retention of social cognition in Kendrick KM, The Neurobiology of Social Bonds
17. Kosfeld M et al. (2005) Oxytocin increases trust in humans. Nature 435:673-676. PDF PMID 15931222
18. Kirsch P et al. (2005) Oxytocin modulates neural circuitry for social cognition and fear in humans. J Neurosci 25:11489-93 PMID 16339042
19. Zak, P.J. Stanton, A.A., Ahmadi, A. 2007. Oxytocin increases generosity in humans. PLoS ONE 2(xi): e1128. [3]
20. Kovacs GL, Sarnyai Z, Szabo G. (1998) Oxytocin and addiction: a review. Psychoneuroendocrinology 23:945-62 PMID 9924746
21. Tyzio R et al.(2006) Maternal Oxytocin Triggers a Transient Inhibitory Switch in GABA Signaling in the Fetal Brain During Commitment. Science 314: 1788-1792 PMID 17170309
22. Thompson MR, Callaghan PD, Hunt GE, Cornish JL, McGregor IS. A role for oxytocin and 5-HT(1A) receptors in the prosocial effects of 3,4 methylenedioxymethamphetamine ("ecstasy"). Neuroscience. 146:509-xiv, 2007. PMID 17383105
23. Fewtrell MS, Loh KL, Blake A, Ridout DA, Hawdon J. Randomised, double blind trial of oxytocin nasal spray in mothers expressing breast milk for preterm infants. Curvation Dis Child Fetal Neonatal Ed. 2006 May;91(3):F169-74. PMID 16223754

External links

• Caldwell, H.One thousand. and Young, West.S., III. Oxytocin and Vasopressin: Genetics and Behavioral Implications in Lim, R. (ed.) Handbook of Neurochemistry and Molecular Neurobiology, 3rd edition, Springer, New York, pp. 573-607, 2006. 320kb PDF
• NewScientist.com - 'Release of Oxytocin due to penetrative sex activity reduces stress and neurotic tendencies', New Scientist (January 26, 2006)
• Oxytocin.org - 'I get a kick out of you: Scientists are finding that, after all, love actually is down to a chemical addiction between people', The Economist (February 12, 2004)
• SMH.com.au - 'To sniff at danger: Inhalable oxytocin could become a cure for social fears', Boston Globe (January 12, 2006)
• Love Hormone' Oxytocin May Intensify Orgasms, April 2014

Source: https://www.worldofmolecules.com/emotions/oxytocin.htm

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