Oxytocin
Systematic (IUPAC) name
?
Identifiers
CAS number	50-56-6
ATC code	H01BB02
PubChem	439302
DrugBank	BTD00016
Chemical data
Formula	C43H66N12O12S2
Mol. mass	1007.19 g/mol
Pharmacokinetic data
Bioavailability	nil
Protein binding	30%
Metabolism	hepatic oxytocinases
Half life	1-6 min
Excretion	Biliary and renal
Therapeutic considerations
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Routes	Intranasal, IV, IM

Oxytocin (Greek: "quick birth") is a mammalian hormone that also acts as a neurotransmitter in the brain. In women, it is released mainly after distension of the cervix and vagina during labor, and after stimulation of the nipples, facilitating birth and breastfeeding, respectively. Oxytocin is released during orgasm in both sexes. In the brain, oxytocin is involved in social recognition and bonding, and might be involved in the formation of trust between people.^{[citation needed]} Also, oxytocin has been known to affect the brain by regulating circadian homeostasis, such as a person's body temperature, activity level, and wakefulness ^[1]. In pharmacology and toxicology, a route of administration is the path by which a drug, fluid, poison or other substance is brought into contact with the body 1. ... Nasal sprays are used for the nasal delivery of a drug or drugs, generally to alleviate cold or allergy symptoms. ... Intravenous therapy or IV therapy is the administration of liquid substances directly into a vein. ... Intramuscular injection is the injection of a substance directly into a muscle. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... Hugo is a masculine name. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... The National Center for Biotechnology Information (NCBI) is part of the US National Library of Medicine (NLM), which is a branch of the US National Institutes of Health. ... Swiss-Prot is a curated biological database of protein sequences created in 1986 by Amos Bairoch during his PhD and developed by the Swiss Institute of Bioinformatics and the European Bioinformatics Institute. ... Short and long arms Chromosome. ... Chromosome 20 is one of the 23 pairs of chromosomes in humans. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the production of milk in female mammary glands and the presence of hair, three middle ear bones used in hearing, and a neocortex region in the... Norepinephrine A hormone (from Greek όρμή - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... Chemical structure of D-aspartic acid, a common amino acid neurotransmitter. ... Italic text // ahh addiing sum spiice iin hurr`` For other uses, see Brain (disambiguation). ... Schematic frontal view of female anatomy The cervix (from Latin neck) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. ... The vagina, (from Latin, literally sheath or scabbard ) is the tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. ... Typical human female nipple and areola. ... Childbirth (also called labour, birth, partus or parturition) is the culmination of a human pregnancy with the emergence of a newborn infant/s from the mothers uterus. ... Breastfeeding an infant Symbol for breastfeeding (Matt Daigle, Mothering magazine contest winner 2006) Breastfeeding is the feeding of an infant or young child with milk from a womans breasts. ... Orgasm is the conclusion of the plateau phase of the sexual response cycle, and is experienced by both males and females. ... The circadian rhythm is a name given to the internal body clock that regulates the (roughly) 24 hour cycle of biological processes in animals and plants. ...

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 brain and to the spinal cord. Magnocellular neurosecretory cells are cells within the supraoptic nucleus and paraventricular nucleus. ... The supraoptic nucleus (SON) is a nucleus of magnocellular neurosecretory cells in the hypothalamus of the mammalian brain. ... The paraventricular nucleus (PVN) is an aggregation of neurons in the hypothalamus, adjacent to the third ventricle. ... The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). ... The posterior pituitary (also called the neurohypophysis) comprises the posterior lobe of the pituitary gland and is part of the endocrine system. ... The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea that sits in a small, bony cavity (pituitary fossa) covered by a dural fold (sellar diaphragm) at the base of the brain. ...

In the pituitary gland, oxytocin is packaged in large, dense-core vesicles, where it is bound to neurophysin I as shown in the inset of the figure; neurophysin is a large peptide fragment of the giant precursor protein molecule from which oxytocin is derived by enzymatic cleavage. The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea that sits in a small, bony cavity (pituitary fossa) covered by a dural fold (sellar diaphragm) at the base of the brain. ... Neurophysin I is a carrier protein with a size of 10 KDa and containing 90 to 97 aminoacids that transports neurohypophysial hormones along axons, from the hypothalamus to the posterior lobe of the pituitary. ... Peptides (from the Greek πεπτος, digestible), are the family of short molecules formed from the linking, in a defined order, of various α-amino acids. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ...

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 large numbers of oxytocin-containing vesicles, which are released by exocytosis when the nerve terminals are depolarised. A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... This page is currently under construction. ...

Structure and relation to vasopressin

Oxytocin structure. Inset shows oxytocin bound to neurophysin

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. One international unit (IU) of oxytocin is the equivalent of about 2 micrograms of pure peptide. Image File history File links Illustration from Crystal structure analysis of deamino-oxytocin: conformational flexibility and receptor binding showing the oxytocin neuropeptide. ... Image File history File links Illustration from Crystal structure analysis of deamino-oxytocin: conformational flexibility and receptor binding showing the oxytocin neuropeptide. ... Peptides (from the Greek πεπτος, digestible), are the family of short molecules formed from the linking, in a defined order, of various α-amino acids. ... Phenylalanine is one of the standard amino acids. ... Cysteine is a naturally occurring, sulfur-containing amino acid that is found in most proteins, although only in small quantities. ... Tyrosine (from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in cheese[1][2]), 4-hydroxyphenylalanine, or 2-amino-3(4-hydroxyphenyl)-propanoic acid, is one of the 20 amino acids that are used by cells to synthesize proteins. ... Isoleucine is one of the 20 natural amino acids, and is coded for in DNA. Its chemical composition is identical to that of leucine, but the arrangement of its atoms is slightly different, resulting in different properties. ... Glutamine is one of the 20 amino acids encoded by the standard genetic code. ... For other articles using the abbreviation or acronym asn see ASN. Asparagine is one of the 20 most common natural amino acids on Earth. ... Cysteine is a naturally occurring, sulfur-containing amino acid that is found in most proteins, although only in small quantities. ... Proline is an α-amino acid with the chemical formula HO2CCH(NH[CH2)3]. L-Proline is one of the twenty DNA-encoded amino acids. ... Leucine is one of the 20 most common amino acids and coded for by DNA. It is isomeric with isoleucine. ... For the plant, see Glycine (plant). ... A disulfide bond (SS-bond), also called a disulfide bridge, is a strong covalent bond between two sulfhydryl groups. ... The molecular mass (abbreviated Mr) of a substance, formerly also called molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... The unified atomic mass unit (u), or dalton (Da), is a small unit of mass used to express atomic masses and molecular masses. ... In pharmacology, the International unit (IU, alternatively abbreviated UI, from French unité internationale) is a unit of measurement for the amount of a substance, based on measured biological activity (or effect). ... The microgram (symbol µg, sometimes mcg) is an SI unit of mass. ...

The structure of oxytocin is very similar to that of vasopressin (cysteine - tyrosine - phenylalanine - glutamine - asparagine - cysteine - proline - arginine - glycine), also a nonapeptide with a sulfur bridge, 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 present in the vasopressin article. Oxytocin and vasopressin were discovered, isolated and synthesized by Vincent du Vigneaud in 1953, work for which he received the Nobel Prize in Chemistry in 1955. Arginine vasopressin (AVP), also known as argipressin or antidiuretic hormone (ADH), is a human hormone that is released when the body is low on water; it causes the kidneys to conserve water, but not salt, by concentrating the urine and reducing urine volume. ... Cysteine is a naturally occurring, sulfur-containing amino acid that is found in most proteins, although only in small quantities. ... Tyrosine (from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in cheese[1][2]), 4-hydroxyphenylalanine, or 2-amino-3(4-hydroxyphenyl)-propanoic acid, is one of the 20 amino acids that are used by cells to synthesize proteins. ... Phe redirects here. ... Glutamine is one of the 20 amino acids encoded by the standard genetic code. ... For other articles using the abbreviation or acronym asn see ASN. Asparagine is one of the 20 most common natural amino acids on Earth. ... Cysteine is a naturally occurring, sulfur-containing amino acid that is found in most proteins, although only in small quantities. ... Proline is an α-amino acid with the chemical formula HO2CCH(NH[CH2)3]. L-Proline is one of the twenty DNA-encoded amino acids. ... Arginine (symbol Arg or R) is an α-amino acid. ... For the plant, see Glycine (plant). ... Peptides (from the Greek πεπτος, digestible), are the family of short molecules formed from the linking, in a defined order, of various α-amino acids. ... Arginine vasopressin (AVP), also known as argipressin or antidiuretic hormone (ADH), is a human hormone that is released when the body is low on water; it causes the kidneys to conserve water, but not salt, by concentrating the urine and reducing urine volume. ... Vincent du Vigneaud (May 18, 1901 - December 11, 1978) was a U.S. biochemist. ... This is a list of Nobel Prize laureates in Chemistry from 1901 to 2006. ...

Oxytocin and vasopressin are the only known hormones released by the human posterior pituitary gland to act at a distance. However, oxytocin neurons make other peptides, including corticotropin-releasing hormone (CRH) and dynorphin, for example, that act locally. The magnocellular neurons that make oxytocin are adjacent to magnocellular neurons that make vasopressin, and are similar in many respects. Corticotropin-releasing hormone (CRH), also called corticotropin-releasing factor (CRF) or corticoliberin, is a polypeptide hormone involved in the stress response. ... Dynorphin (Dyn) is a popular and powerful opioid ligand. ...

Actions

Oxytocin has peripheral (hormonal) actions, and also has actions in the brain. The actions of oxytocin are mediated by specific, high affinity oxytocin receptors. The oxytocin receptor is a G-protein-coupled receptor which requires Mg²⁺ and cholesterol. It belongs to the rhodopsin-type (class I) group of G-protein-coupled receptors. The seven transmembrane α-helix structure of a G-protein-coupled receptor. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Cholesterol is a sterol (a combination steroid and alcohol) and a lipid found in the cell membranes of all body tissues, and transported in the blood plasma of all animals. ... A rhodopsin molecule (yellow) with bound retinal (orange), embedded in a cell membrane (lipids shown as green, head groups as red/blue). ...

Peripheral (hormonal) actions

The peripheral actions of oxytocin mainly reflect secretion from the pituitary gland. (See oxytocin receptor for more detail on its action.) Oxytocin receptors are expressed by the myoepithelial cells of the mammary gland, and in both the myometrium and endometrium of the uterus at the end of pregnancy. ...

• Letdown reflex – in lactating (breastfeeding) mothers, oxytocin acts at the mammary glands, causing milk to be 'let down' into a collecting chamber, from where it can be extracted by sucking at the nipple. Sucking by the infant at the nipple is relayed by spinal nerves to the hypothalamus. The stimulation causes neurons that make oxytocin to fire action potentials in intermittent bursts; these bursts result in the secretion of pulses of oxytocin from the neurosecretory nerve terminals of the pituitary gland.
• Uterine contraction – important for cervical dilation before birth and causes contractions during the second and third stages of labor. Oxytocin release during breastfeeding causes mild but often painful uterine contractions during the first few weeks of lactation. This also serves to assist the uterus in clotting the placental attachment point postpartum. However, in knockout mice lacking the oxytocin receptor, reproductive behavior and parturition is normal.^[2]
• Oxytocin is secreted into the blood at orgasm – in both males and females.^[3] In males, oxytocin may facilitate sperm transport in ejaculation.
• Due to its similarity to vasopressin, it can reduce the excretion of urine slightly. More important, in several species, oxytocin can stimulate sodium excretion from the kidneys (natriuresis), and in humans, high doses of oxytocin can result in hyponatremia.
• Oxytocin and oxytocin receptors are also found in the heart in some rodents, and the hormone may play a role in the embryonal development of the heart by promoting cardiomyocyte differentiation. ^[4][5] However, the absence of either oxytocin or its receptor in knockout mice has not been reported to produce cardiac insufficiencies.^[2]

Breastfeeding an infant Symbol for breastfeeding (Matt Daigle, Mothering magazine contest winner 2006) Breastfeeding is the feeding of an infant or young child with milk from a womans breasts. ... Kittens nursing Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young. ... Mammary glands are the organs that, in the female mammal, produce milk for the sustenance of the young. ... Typical human female nipple and areola. ... A human infant In basic English usage, an infant is defined as a human child at the youngest stage of life, especially before they can walk or simply a child before the age of one. ... The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). ... In medicine (obstetrics), a contraction is a forceful motion of the uterus, generated by the release of oxytocin (quick labor) by the pituitary gland, culminating in childbirth. ... Cervical dilation is the dilation (widening) of the cervix during childbirth. ... It has been suggested that this article or section be merged into Gene knockout. ... Orgasm is the conclusion of the plateau phase of the sexual response cycle, and is experienced by both males and females. ... Ejaculation is the ejecting of semen from the penis, and is usually accompanied by orgasm. ... Arginine vasopressin (AVP), also known as argipressin or antidiuretic hormone (ADH), is a human hormone that is released when the body is low on water; it causes the kidneys to conserve water, but not salt, by concentrating the urine and reducing urine volume. ... This article or section is in need of attention from an expert on the subject. ... The electrolyte disturbance hyponatremia or hyponatraemia exists in humans when the sodium level in the plasma falls below 135 mmol/l. ... The heart and lungs, from an older edition of Grays Anatomy. ... Global view of a neuromuscular junction: 1. ... It has been suggested that this article or section be merged into Gene knockout. ...

Actions of oxytocin within the brain

Oxytocin secreted from the pituitary gland cannot re-enter the brain because of the blood-brain barrier. Instead, the behavioral effects 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. Freeze-fracture morphology of the blood-brain barrier of a rat The blood-brain barrier (abbreviated BBB) is a membranic structure that acts primarily to protect the brain from chemicals in the blood, while still allowing essential metabolic function. ... Look up Amygdala in Wiktionary, the free dictionary. ... The ventromedial nucleus of the hypothalamus (sometimes referred to as the ventromedial hypothalamus) has two parts; The superior and anterior parts. ... Look up septum in Wiktionary, the free dictionary. ... The brain stem is the stalk of the brain below the cerebral hemispheres. ...

• Sexual arousal. Oxytocin injected into the cerebrospinal fluid causes spontaneous erections in rats,^[6] reflecting actions in the hypothalamus and spinal cord.
• Bonding. In the Prairie Vole, oxytocin released into the brain of the female during sexual activity is important for forming a monogamous pair bond with her sexual partner. Vasopressin appears to have a similar effect in males ^[7]. In people, plasma concentrations of oxytocin have been reported to be higher amongst people who claim to be falling in love. Oxytocin has a role in social behaviors in many species, and so it seems likely that it has similar roles in humans.
• Autism. It has been suggested that deficiencies in oxytocin pathways in the brain might be a feature of autism. A recent study found a decrease in autism spectrum repetitive behaviors when oxytocin was administered intravenously^[8].
• Maternal behavior. Sheep and rat females given oxytocin antagonists after giving birth do not exhibit typical maternal behavior. By contrast, virgin female sheep show maternal behavior towards foreign lambs upon cerebrospinal fluid infusion of oxytocin, which they would not do otherwise. ^[9]
• Increasing trust and reducing fear. In a risky investment game, experimental subjects given nasally administered oxytocin displayed "the highest level of trust" twice as often as the control group. Subjects who were told that they were interacting with a computer showed no such reaction, leading to the conclusion that oxytocin was not merely affecting risk-aversion.^[10] Nasally-administered oxytocin has also been reported to reduce fear, possibly by inhibiting the amygdala (which is thought to be responsible for fear responses).^[11] There is no conclusive evidence for access of oxytocin to the brain through intranasal administration, however.

• According to some studies in animals, oxytocin inhibits the development of tolerance to various addictive drugs (opiates, cocaine, alcohol) and reduces withdrawal symptoms.^[12]
• 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 damage.^[13]
• Certain learning and memory functions are impaired by centrally-administered oxytocin.^[6]
• The illicit party drug MDMA (ecstasy) is thought to produce most of it's effects of feeling love, empathy and connection to others by dramatically increasing the activity of oxytocin in the brain, contrary to the common misconception of these effects being due to MDMA's effects on serotonin activity. Research has shown that when this drug-induced effect on oxytocin is blocked then most of the aforementioned emphatic effects do not occur.

Cerebrospinal fluid (CSF), Liquor cerebrospinalis, is a clear bodily fluid that occupies the subarachnoid space in the brain (the space between the skull and the cerebral cortex—more specifically, between the arachnoid and pia layers of the meninges). ... The erection of the penis, clitoris or a nipple is its enlarged and firm state. ... Binomial name Microtus ochrogaster (Wagner, 1842) The Prairie Vole, Microtus ochrogaster, is a small vole found in central North America. ... Arginine vasopressin (AVP), also known as argipressin or antidiuretic hormone (ADH), is a human hormone that is released when the body is low on water; it causes the kidneys to conserve water, but not salt, by concentrating the urine and reducing urine volume. ... Love is any of a number of emotions and experiences related to a sense of strong affection or profound oneness. ... Autism is classified by the World Health Organization and American Psychological Association as a developmental disability that results from a disorder of the human central nervous system. ... A mother holds up her child. ... Antagonists In medicine and biology, a receptor antagonist is a ligand that inhibits the function of an agonist and inverse agonist for a specific receptor. ... Cerebrospinal fluid (CSF), Liquor cerebrospinalis, is a clear bodily fluid that occupies the subarachnoid space in the brain (the space between the skull and the cerebral cortex—more specifically, between the arachnoid and pia layers of the meninges). ... Trust is the belief in the good character of one party, presumed to seek to fulfill policies, ethical codes, law and their previous promises. ... Risk aversion is a concept in economics, finance, and psychology explaining the behaviour of consumers and investors under uncertainty. ... Look up Amygdala in Wiktionary, the free dictionary. ... Scoring the poppy pod. ... Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. ... Grain alcohol redirects here. ... Withdrawal, also known as withdrawal syndrome, refers to the characteristic signs and symptoms that appear when a drug that causes physical dependence is regularly used for a long time and then suddenly discontinued or decreased in dosage. ... Gaba may refer to: Gabâ or gabaa (Philippines), the concept of negative karma of the Cebuano people GABA, the gamma-amino-butyric acid neurotransmitter GABA receptor, in biology, receptors with GABA as their endogenous ligand Gaba 1 to 1, an English conversational school in Japan Marianne Gaba, a US model... Hypoxia is a pathological condition in which the body as a whole (generalised hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply. ... ecstasy and religious ecstasy MDMA, most commonly known today by the street name ecstasy, is a synthetic entactogen of the phenethylamine family whose primary effect is to stimulate the brain to rapidly secrete large amounts of serotonin, causing a general sense of openness, empathy, energy, euphoria, and well-being. ... Serotonin (5-hydroxytryptamine, or 5-HT) is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system (CNS) and enterochromaffin cells in the gastrointestinal tract of animals including humans. ...

Drug forms

Synthetic oxytocin is sold as medication under the trade names Pitocin and Syntocinon and also 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 brain by the blood-brain barrier. Drugs administered by nasal spray are thought to have better access to the CNS. Oxytocin nasal sprays have been used to stimulate breastfeeding. It has been suggested that Blockbuster drug be merged into this article or section. ... A generic drug (pl. ... Upper and Lower gastrointestinal tract The gastrointestinal tract (GI tract), also called the digestive tract, or the alimentary canal, is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. ... Nasal sprays are used for the nasal delivery of a drug or drugs, generally to alleviate cold or allergy symptoms. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Intravenous therapy or IV therapy is the administration of liquid substances directly into a vein. ... Freeze-fracture morphology of the blood-brain barrier of a rat The blood-brain barrier (abbreviated BBB) is a membranic structure that acts primarily to protect the brain from chemicals in the blood, while still allowing essential metabolic function. ... A diagram showing the CNS: 1. ...

Injected oxytocin analogues are used to induce labour and support labour in case of non-progression of parturition. It has largely replaced ergotamine as the principal agent to increase uterine tone in acute postpartum haemorrhage. Oxytocin is also used in veterinary medicine to facilitate birth and to increase milk production. The tocolytic agent atosiban (Tractocile®) acts as 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). Ergotamine is a vasoconstrictor used for migraine prevention and is sometimes mixed with caffeine. ... Veterinary medicine is the application of medical, diagnostic, and therapeutic principles to companion, domestic, exotic, wildlife, and production animals. ... Tocolytics are medications used to suppress premature labor (from the Greek tokos, childbirth, and lytic, capable of dissolving). ... Atosiban (Tractocile®) is an inhibitor of the hormone oxytocin, and is used in premature labor. ... Antagonists In medicine and biology, a receptor antagonist is a ligand that inhibits the function of an agonist and inverse agonist for a specific receptor. ... Ritodrine hydrochloride (Yutopar®) is a tocolytic drug, used to stop premature labor. ... Salbutamol (INN) or albuterol (USAN) is a short-acting β2-adrenergic receptor agonist used for the relief of bronchospasm in conditions such as asthma and COPD. Salbutamol sulphate is usually given by the inhaled route for direct effect on bronchial smooth muscle. ... The drug Terbutaline (trade names Brethine, Bricanyl, or Brethaire) is a β2-adrenergic receptor agonist, used as a fast-acting bronchodilator and off-label to delay premature labour as a tocolytic. ...

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. Social anxiety is an experience of fear, apprehension or worry regarding social situations and being evaluated by others. ... To meet Wikipedias quality standards, this article or section may require cleanup because it is in list format. ...

Potential adverse reactions

Oxytocin is relatively safe when used at recommended doses. Potential side effects include:^{[citation needed]} An adverse drug reaction (abbreviated ADR) is a term to describe the unwanted, negative consequences sometimes associated with the use of medications. ...

• Central nervous system: Subarachnoid hemorrhage, seizures.
• Cardiovascular: Increased heart rate, blood pressure, systemic venous return, cardiac output, and arrhythmias.
• Genitourinary: Impaired uterine blood flow, pelvic hematoma, tetanic uterine contractions, uterine rupture, postpartum hemorrhage.

A diagram showing the CNS: 1. ... A subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space surrounding the brain, i. ... This article is about the medical term, epileptic seizure, as distinct from a non-epileptic seizure. ... The circulatory system or cardiovascular system is the organ system which circulates blood around the body of most animals. ... This article or section does not cite any references or sources. ... Cardiac output is the volume of blood being pumped by the heart, in particular a ventricle in a minute. ... Cardiac arrhythmia is a group of conditions in which the electrical activity of the heart is irregular or is faster or slower than normal. ... This page is a candidate to be moved to Wiktionary. ...

Evolution

Virtually all vertebrates have an oxytocin-like nonapeptide hormone that supports reproductive functions and a vasopressin-like nonapeptide hormone involved in water regulation. The two genes are always located close to each other (less than 15,000 bases apart) on the same chromosome and are transcribed in opposite directions. It is thought that the two genes resulted from a gene duplication event; the ancestral gene is estimated to be about 500 million years old and is found in cyclostomes (modern members of the Agnatha).^[6] Classes and Clades See below Male and female Superb Fairy-wren Vertebrates are members of the subphylum Vertebrata (within the phylum Chordata), specifically, those chordates with backbones or spinal columns. ... Peptides (from the Greek πεπτος, digestible), are the family of short molecules formed from the linking, in a defined order, of various α-amino acids. ... Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ... Schematic of a region of a chromosome before and after a duplication event Gene duplication occurs when an error in homologous recombination, a retrotransposition event, or duplication of an entire chromosome leads to the duplication of a region of DNA containing a gene [1]. The significance of this process for... Cyclostome is a biological term (from the Greek for round mouth) used in two different senses: for the extant members of the Agnatha, i. ... Idealized agnatha. ...

References

Nature is one of the most prominent scientific journals, first published on 4 November 1869. ...

External links

• ColoState.edu - 'Oxytocin in a nine amino acid peptide that is synthesized in hypothalamic neurons and transported down axons of the posterior pituitary for secretion into blood' (from on-line textbook, Pathophysiology of the Endocrine System), R.A. Bowen

• Metroactive.com - 'Love Is a Drug: Once the realm of poets, artists and philosophers, love has been exposed as biochemistry, Dan Pulcrano, Metro Silicon Valley (February 9, 2005)
• NewScientist.com - 'Release of Oxytocin due to penetrative sex 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 really 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)

• Hug the Monkey - A weblog devoted entirely to oxytocin