A vasopressin receptor is a GPCR whose ligand is vasopressin . V 1 , V 2 and V 3 subtypes of the vasopressin receptor are known. These three subtypes differ in localization, function, and signal transduction mechanisms [1] .
Content
- 1 Subtypes of receptors
- 1.1 Receptors V 1
- 1.2 V 2 receptors
- 1.3 V 3 receptors
- 2 Functions
- 3 notes
Receptor Subtypes
There are three subtypes of the vasopressin receptor: V 1A (V 1 ), V 1B (V 3 ) and V 2 [2] .
| Genes | Receptors | Signaling paths | Location | Functions |
|---|---|---|---|---|
| V 1A (V 1 ) | G-protein, phosphatidylinositol / calcium | smooth muscles of blood vessels, platelets , hepatocytes | vasoconstriction, myocardial hypotrophy, platelet accumulation, glycogenolysis , uterine contraction | |
| V 1B (V 3 ) | G-protein, phosphatidylinositol / calcium | Anterior Pituitary Gland | ACTH secretion, prolactin , endorphins | |
| V 2 | G s protein, adenylate cyclase / cAMP | membrane of the collecting tube, vascular endothelium and smooth muscle cells of blood vessels | insertion of water channels AQP-2 into the apical membrane, induction of AQP-2 synthesis |
Receptors V 1
Receptors V 1 (V 1 Rs) are found in high concentrations on the smooth muscles of blood vessels and cause their narrowing by an increase in intracellular calcium through the cascade of phosphatidylinositol bisphosphonate (phosphatidylinositol-bisphosphonate). V 1 R has also been found on cardiac myocytes . V 1 are located in the brain, testis, superior cervical nerve ganglion, liver, blood vessels and in the medulla of the kidneys.
V 1 R is present on platelets , it causes an increase in intracellular calcium, facilitating thrombosis .
V 1 Rs are found in the kidney, where they are found in large numbers on the direct vessels of the kidney and epithelial cells of the collecting duct . Vasopressin acts on the vasculature of the medulla of the kidney through V 1 R to reduce blood flow in the inside without affecting blood flow in the outside. V 1 Rs on the membrane of the collecting tube of the kidney limits the anti-diuretic effect of vasopressin. In addition, vasopressin selectively reduces the efferent small arteries of the kidneys, probably through V 1 R ( but not arteries ) [2] .
Receptors V 2
The V 2 receptor (V 2 R) differs from V 1 R primarily in the number of sites susceptible to glycosylation .
The well-known antidiuretic (antidiuretic) effect of vasopressin is due to the activation of the V 2 R receptor [2] . Vasopressin regulates the excretion of water by the kidneys, increasing the osmotic water permeability of the membranes of the collecting tubules. This effect is associated with the activation of V 2 R with Gs , resulting in an increase in the intracellular concentration of cAMP . A high concentration of cAMP activates the fusion of aquaporin-2- bearing vesicles with the apical plasma membrane of the collecting tube cells, increasing water reabsorption [2] .
Receptors V 3
The human V 3 receptor (V 3 R, formerly known as V1BR) is a pituitary receptor associated with the G protein . Due to the low level of expression, it has only recently been characterized. Its 424 amino acid sequence has a similarity level of 45%, 39% and 45%, respectively, with V 1 R, V 2 R and the oxytocin receptor (OTR). The pharmacological profile of V 3 R distinguishes it from the human V 1 R; V 3 R activates several signaling pathways through various G-proteins , depending on the level of receptor expression [2] .
Functions
Although all three of these proteins are associated with G-protein ( GPCR s), activation of AVPR1A and AVPR1B stimulates phospholipase C , while activation of AVPR2 stimulates adenylate cyclase . These three vasopressin receptors have their unique tissue locations. AVPR1A are expressed in blood vessel smooth muscle cells, hepatocytes , platelets , brain cells, and uterine cells. AVPR1B are located on the cells of the adenohypophysis and in other parts of the brain, especially on the CA2 hippocampal pyramidal neurons. AVPR2 are located in the renal tube, prevail in the peripheral and collecting tubes, in the embryonic lung tissue and on lung cancer cells. AVPR2 is also found in the liver, where its stimulation leads to the secretion of many coagulation factors into the bloodstream. In the kidney, the primary function of AVPR2 is that, in response to arginine-vasopressin, it triggers the concentration of urine and maintains water homeostasis in the body [3] .
Notes
- ↑ Greenberg A., Verbalis JG Vasopressin receptor antagonists (English) // Kidney Int. : journal. - 2006 .-- June ( vol. 69 , no. 12 ). - P. 2124-2130 . - DOI : 10.1038 / sj.ki.5000432 . - PMID 16672911 .
- ↑ 1 2 3 4 5 Holmes CL, Landry DW, Granton JT Science review: Vasopressin and the cardiovascular system part 1 - receptor physiology (Eng.) // Crit Care : journal. - 2003 .-- December ( vol. 7 , no. 6 ). - P. 427-434 . - DOI : 10.1186 / cc2337 . - PMID 14624682 .
- ↑ Spanakis E., Milord E., Gragnoli C. AVPR2 variants and mutations in nephrogenic diabetes insipidus: review and missense mutation significance (English) // J. Cell. Physiol. : journal. - 2008 .-- December ( vol. 217 , no. 3 ). - P. 605-617 . - DOI : 10.1002 / jcp.21552 . - PMID 18726898 .