Compilation of free information about human parts, their function, assembly, repair, and maintenance
Vasopressin
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| Space-filling model of arginine vasopressin | |
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arginine vasopressin (antidiuretic hormone)
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| Identifiers | |
| Symbol | AVP, |
| Alt. Symbols | VP, ADH |
| Entrez | 551 |
| HUGO | 894 |
| OMIM | 192340 |
| RefSeq | NM_000490 |
| UniProt | P01185 |
| Other data | |
| Locus | Chr. 20 p13 |
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. It also raises blood pressure by inducing moderate vasoconstriction. It has various effects in the brain.
A very similar substance, lysine vasopressin (LVP) or lypressin, has the same function in pigs and is often used in human therapy.
Vasopressin is a peptide hormone. It is derived from a preprohormone precursor that is synthesized in the hypothalamus, from which it is liberated during transport to the posterior pituitary. Most of it is stored in the posterior part of the pituitary gland to be released into the blood stream; some of it is also released directly into the brain.
Physiology
Action
AVP allows water reabsorption by the introduction of additional water channels in cortical and inner medullary collecting ducts.
Control
Vasopressin is secreted from the posterior pituitary gland in response to reductions in plasma volume and in response to increases in the plasma osmolality:
- Secretion in response to reduced plasma volume is activated by pressure receptors in the veins, atria, and carotids.
- Secretion in response to increases in plasma osmotic pressure is mediated by osmoreceptors in the hypothalamus.
The neurons that make vasopressin, in the supraoptic nucleus and paraventricular nucleus, are themselves osmoreceptors, but they also receive synaptic input from other osmoreceptors located in regions adjacent to the anterior wall of the third ventricle. These regions include the organum vasculosum of the lamina terminalis and the subfornical organ.
Many factors influence the secretion of vasopressin:
- Ethanol and caffeine reduce vasopressin secretion. The resulting decrease in water reabsorption by the kidneys leads to a higher urine output. Coffee is an example of a food product that suppresses the body's release of antidiuretic hormones, due to its level of caffeine. This intake of caffeine causes the body to lose more water and may lead to dehydration if consumed excessively.
- Angiotensin II stimulates the secretion of vasopressin.[1]
Sources
The vasopressin that is measured in peripheral blood is almost all derived from secretion from the posterior pituitary gland (except in cases of vasopressin-secreting tumours). However there are two other sources of vasopressin with important local effects:
- Vasopressin is secreted from parvocellular neurons of the paraventricular nucleus at the median eminence into the short portal vessels of the pituitary stalk. These vessels carry the peptide directly to the anterior pituitary gland, where it is an important releasing factor for ACTH, acting in conjunction with CRH.
- Vasopressin is also released into the brain by several different populations of neurons (see below).
Effects on the Central Nervous System (CNS)
Vasopressin released within the brain has many actions:
- It has been implicated in memory formation, including delayed reflexes, image, short- and long-term memory, though the mechanism remains unknown, and these findings are controversial. However, the synthetic vasopressin analogue desmopressin has come to interest as a likely nootropic.
- Vasopressin is released into the brain in a circadian rhythm by neurons of the suprachiasmatic nucleus of the hypothalamus.
- Vasopressin released from centrally-projecting hypothalamic neurons is involved in aggression, blood pressure regulation and temperature regulation.
In recent years there has been particular interest in the role of vasopressin in social behavior. It is thought that vasopressin, released into the brain during sexual activity, initiates and sustains patterns of activity that support the pair-bond between the sexual partners; in particular, vasopressin seems to induce the male to become aggressive towards other males.
Evidence for this comes from experimental studies in several species, which indicate that the precise distribution of vasopressin and vasopressin receptors in the brain is associated with species-typical patterns of social behavior. In particular, there are consistent differences between monogamous species and promiscuous species in the distribution of vasopressin receptors, and sometimes in the distribution of vasopressin-containing axons, even when closely-related species are compared. Moreover, studies involving either injecting vasopressin agonists into the brain, or blocking the actions of vasopressin, support the hypothesis that vasopressin is involved in aggression towards other males. There is also evidence that differences in the vasopressin receptor gene between individual members of a species might be predictive of differences in social behavior.
Summary Table
Here is a table summarizing some of the actions of Avp at its three receptors, differently expressed in different tissues and exerting different actions:
| Type | Second messenger system | Locations | Actions |
| AVPR1A | phosphatidylinositol/calcium | liver, kidney, peripheral vasculature, [[brain | vasoconstriction, gluconeogenesis, platelet aggregation, and release of factor VIII and von Willebrand factor; social recognition[2], circadian tau[3] |
| AVPR1B | phosphatidylinositol/calcium | pituitary gland, brain | adrenocorticotropic hormone secretion in response to stress[4]; social interpretation to olfactory cues[5] |
| AVPR2 | adenylate cyclase/cAMP | apical membrane of the cells lining the collecting ducts of the kidneys (especially the cortical and outer medullary collecting ducts) | insertion of aquaporin-2 (AQP2) channels (water channels). This allows water to be reabsorbed down an osmotic gradient, and so the urine is more concentrated. Release of von Willebrand factor and surface expression of P-selectin through exocytosis of Weibel-Palade bodies from endothelial cells[6][7] |
Structure and relation to oxytocin
The vasopressins are peptides consisting of nine amino acids (nonapeptides). (NB: the value in the table above of 164 amino acids is that obtained before the hormone is activated by cleavage). The amino acid sequence of arginine vasopressin is Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly, with the cysteine residues forming a sulfur bridge. Lysine vasopressin has a lysine in place of the arginine.
The structure of oxytocin is very similar to that of the vasopressins: it is also a nonapeptide with a sulfur bridge and its amino acid sequence differs at only two positions (see table below). The two genes are located on the same chromosome separated by a relatively small distance of less than 15,000 bases in various species. The magnocellular neurons that make vasopressin are adjacent to magnocellular neurons that make oxytocin, and are similar in many respects. The similarity of the two peptides can cause some cross-reactions: oxytocin has a slight antidiuretic function, and high levels of vasopressin can cause uterine contractions.
Here is a table showing the superfamily of vasopressin and oxytocin neuropeptides:
Vertebrate Vasopressin Family Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH2 Argipressin (AVP, ADH) Most mammals Cys-Tyr-Phe-Gln-Asn-
Cys-Pro-Lys-Gly-NH2Lypressin (LVP) Pigs, hippos, warthogs, some marsupials Cys-Phe-Phe-Gln-Asn-
Cys-Pro-Arg-Gly-NH2Phenypressin Some marsupials Cys-Tyr-Ile-Gln-Asn-
Cys-Pro-Arg-Gly-NH2Vasotocin† Non-mammals Vertebrate Oxytocin Family Cys-Tyr-Ile-Gln-Asn-Cys-
Pro-Leu-Gly-NH2Oxytocin (OXT) Most mammals, ratfish Cys-Tyr-Ile-Gln-Asn-
Cys-Pro-Ile-Gly-NH2Mesotocin Most marsupials, all birds, reptiles,
amphibians, lungfishesCys-Tyr-Ile-Gln-Ser-
Cys-Pro-Ile-Gly-NH2Seritocin Frogs Cys-Tyr-Ile-Ser-Asn-
Cys-Pro-Ile-Gly-NH2Isotocin Bony fishes Cys-Tyr-Ile-Ser-Asn-
Cys-Pro-Gln-Gly-NH2Glumitocin Skates Cys-Tyr-Ile-Asn/Gln-
Asn-Cys-Pro-Leu/Val-
Gly-NH2Various tocins Sharks Invertebrate VP/OT Superfamily Cys-Leu-Ile-Thr-Asn-
Cys-Pro-Arg-Gly-NH2Diuretic Hormone Locust Cys-Phe-Val-Arg-Asn-
Cys-Pro-Thr-Gly-NH2Annetocin Earthworm Cys-Phe-Ile-Arg-Asn-
Cys-Pro-Lys-Gly-NH2Lys-Connopressin Geography & imperial
cone snail, pond snail,
sea hare, leechCys-Ile-Ile-Arg-Asn-
Cys-Pro-Arg-Gly-NH2Arg-Connopressin Striped cone snail Cys-Tyr-Phe-Arg-Asn-
Cys-Pro-Ile-Gly-NH2Cephalotocin Octopus Cys-Phe-Trp-Thr-Ser-
Cys-Pro-Ile-Gly-NH2Octopressin Octopus †Vasotocin is the evolutionary progenitor of all the vertebrate
neurohypophysial hormones. Only vasotocin found in hagfish &
lampreys (Agnatha appeared 500 million years ago)
Role in disease
Decreased vasopressin release or decreased renal sensitivity to vasopressin leads to diabetes insipidus, a condition featuring hypernatremia (increased blood sodium content), polyuria (excess urine production), and polydipsia (thirst).
High levels of vasopressin secretion (syndrome of inappropriate antidiuretic hormone, SIADH) and resultant hyponatremia (low blood sodium levels) occurs in brain diseases and conditions of the lungs. In the perioperative period, the effects of surgical stress and some commonly used medications (e.g., opiates, syntocinon, anti-emetics) lead to a similar state of excess vasopressin secretion. This may cause mild hyponatremia for several days.
Pharmacology
Vasopressin analogues
Vasopressin agonists are used therapeutically in various conditions, and its long-acting synthetic analogue desmopressin is used in conditions featuring low vasopressin secretion, as well as for control of bleeding (in some forms of von Willebrand disease) and in extreme cases of bedwetting by children. Terlipressin and related analogues are used as vasocontrictors in certain conditions. Use of vasopressin analogues for esophageal varices commenced in 1970.[8]
Vasopressin infusion has been used as a second line of
management in
septic shock patients not responding to high dose of
inotropes (e.g.,
dopamine or
norepinephrine). It had been shown to be more effective than
epinephrine in
asystolic
cardiac arrest.[9]
While not all studies are in agreement, a 2006 study of out-of
hospital cardiac arrests has added to the evidence for the
superiority of vasopressin in this situation.[10]
Vasopressin receptor inhibition
Demeclocycline, a tetracycline antibiotic, is sometimes used to block the action of vasopressin in the kidney in hyponatremia due to inappropriately high secretion of vasopressin (SIADH, see above), when fluid restriction has failed. A new class of medication (conivaptan, tolvaptan, relcovaptan, lixivaptan) acts by inhibiting the action of vasopressin on its receptors (V1 and V2), with tolvaptan acting on V1a and V2 and the remainder mainly on V1a receptors. The same class of drugs is also being studied in congestive heart failure.
References
- ^ Vander, A.J., Renal Physiology, McGraw-Hill, 1991.
- ^ Bielsky IF, Hu SB, Szegda KL, Westphal H, Young LJ. Profound impairment in social recognition and reduction in anxiety-like behavior in vasopressin V1a receptor knockout mice.Neuropsychopharmacology. 2004; 29:483-93. PMID 14647484
- ^ Wersinger SR, Caldwell HK, Martinez L, Gold P, Hu SB, Young WS 3rd. Vasopressin 1a receptor knockout mice have a subtle olfactory deficit but normal aggression. Genes Brain Behav. 2006 Nov 3; [Epub ahead of print] PMID 17083331
- ^ Lolait SJ, Stewart LQ, Jessop DS, Young WS 3rd, O'Carroll AM. The hypothalamic-pituitary-adrenal axis response to stress in mice lacking functional vasopressin V1b receptors. Endocrinology. 2007;148:849-56. PMID 17122081
- ^ Wersinger SR, Kelliher KR, Zufall F, Lolait SJ, O'Carroll AM, Young WS 3rd. Social motivation is reduced in vasopressin 1b receptor null mice despite normal performance in an olfactory discrimination task. Horm Behav. 2004;46:638-45. PMID 15555506
- ^ Kanwar S, Woodman RC, Poon MC, Murohara T, Lefer AM, Davenpeck KL, Kubes P. Desmopressin induces endothelial P-selectin expression and leukocyte rolling in postcapillary venules.Blood. 1995 Oct 1;86(7):2760-6. PMID 7545469
- ^ Kaufmann JE, Oksche A, Wollheim CB, Gunther G, Rosenthal W, Vischer UM. Vasopressin-induced von Willebrand factor secretion from endothelial cells involves V2 receptors and cAMP. J Clin Invest. 2000 Jul;106(1):107-16. PMID 10880054
- ^ Baum S, Nusbaum M, Tumen HJ. The control of gastrointestinal hemorrhage by selective mesenteric infusion of pitressin. Gastroenterology 1970;58:926.
- ^ Wenzel V, Krismer AC, Arntz HR, Sitter H, Stadlbauer KH, Lindner KH; European Resuscitation Council Vasopressor during Cardiopulmonary Resuscitation Study Group. A comparison of vasopressin and epinephrine for out-of-hospital cardiopulmonary resuscitation. N Engl J Med 2004;350:105-13. PMID 14711909.
- ^ Grmec S, Mally S. Vasopressin improves outcome in out-of-hospital cardiopulmonary resuscitation of ventricular fibrillation and pulseless ventricular tachycardia: an observational cohort study. Crit Care. 2006 Feb;10(1):R13. PMID 16420660.
Further Reading
- Brenner & Rector's The Kidney, 7th ed., Saunders, 2004. Full Text with MDConsult subscription
- Caldwell, H.K. and Young, W.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
External links
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| Filtration | Ultrafiltration - Countercurrent exchange |
| Hormones affecting filtration | Antidiuretic hormone (ADH) - Aldosterone - Atrial natriuretic peptide |
| Endocrine | Renin - Erythropoietin (EPO) - Calcitriol (Active vitamin D) - Prostaglandins |
| Assessing Renal function / Measures of dialysis | Glomerular filtration rate - Creatinine clearance - Renal clearance ratio - Urea reduction ratio - Kt/V - Standardized Kt/V - Hemodialysis product |
| Acid base physiology | Fluid balance - Darrow Yannet diagram - Body water - Interstitial fluid - Extracellular fluid - Intracellular fluid/Cytosol - Plasma - Transcellular fluid - Base excess - Davenport diagram - Anion gap |
| Buffering/compensation | Bicarbonate buffering system - Respiratory compensation - Renal compensation |
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| Hypothalamic | Somatostatin - CRH - GnRH - GHRH - Orexins - TRH - POMC (ACTH, MSH, Lipotropin) |
| Gastrointestinal hormones | Cholecystokinin - Gastric inhibitory polypeptide - Gastrin - Motilin - Secretin - Vasoactive intestinal peptide |
| Other hormones | Vasopressin - Calcitonin - |
| Other | Angiotensin - Bombesin/Neuromedin B - Calcitonin gene-related peptide - Carnosine - Delta sleep-inducing peptide - FMRFamide - Galanin - Gastrin releasing peptide - Kinins (Bradykinin, Tachykinins ) - Neuropeptide Y - Neurophysins - Neurotensin - Opioid peptide - Pancreatic polypeptide - Pituitary adenylate cyclase activating peptide |
The content of this section is licensed under the GNU Free Documentation License (local copy). It uses material from the Wikipedia article "Vasopressin" modified December 22, 2007 with previous authors listed in its history.
