Endothelins are peptides with receptors and effects in many body organs. Endothelin constricts blood vessels and raises blood pressure. The endothelins are normally kept in balance by other mechanisms, but when overexpressed, they contribute to high blood pressure (hypertension), heart disease, and potentially other diseases.
There are at least four known endothelin receptors, ETA, ETB1, ETB2 and ETC, all of which are G protein-coupled receptors whose activation result in elevation of intracellular-free calcium, which constricts the smooth muscles of the blood vessels, raising blood pressure, or relaxes the smooth muscles of the blood vessels, lowering blood pressure, among other functions.
The thyrotropin receptor is a receptor that responds to thyroid-stimulating hormone and stimulates the production of thyroxine (T4) and triiodothyronine (T3). The TSH receptor is a member of the G protein-coupled receptor superfamily of integral membrane proteins and is coupled to the Gs protein.
The tachykinin receptor 1 (TACR1) also known as neurokinin 1 receptor (NK1R) or substance P receptor (SPR) is a G protein coupled receptor found in the central nervous system and peripheral nervous system. The endogenous ligand for this receptor is Substance P, although it has some affinity for other tachykinins. The protein is the product of the TACR1 gene.
Angiotensin II receptor type 1(AT1) is the best characterized angiotensin receptor. It is encoded in humans by the AGTR1 gene. AT1 has vasopressor effects and regulates aldosterone secretion. It is an important effector controlling blood pressure and volume in the cardiovascular system. Angiotensin II receptor blockers are drugs indicated for hypertension, diabetic nephropathy and congestive heart failure.
Endothelin receptor type B, also known as ETB is a protein that in humans is encoded by the EDNRB gene.
Endothelin receptor type A, also known as ETA, is a human G protein-coupled receptor.
Tachykinin receptor 3, also known as TACR3, is a protein which in humans is encoded by the TACR3 gene.
G-protein coupled receptor 139 (GPC139) is a protein that in humans is encoded by the GPR139 gene. Recent research ('21) has shown that mice with loss of GCP139 experience schizophrenia-like symptomatology that is rescued with the dopamine receptor antagonist haloperidol and the μ-opioid receptor antagonist naltrexone; as well, the recently developed, potent, and GPR139 receptor selective agonist TAK-041 is currently undergoing trials to gauge the efficacy for treating psychiatric conditions such as major depressive disorder and the negative symptoms of schizophrenia.
BQ-123, also known as cyclo(-D-Trp-D-Asp-Pro-D-Val-Leu-), is a cyclic pentapeptide that was first isolated from a fermentation broth of Streptomyces misakiensis in 1991. NMR studies indicate that the polypeptide backbone consists of a type II beta turn and an inverse gamma turn. The side-chains adopt different orientations depending on the solvent used. The proline carbonyl oxygen atom located at the onset of a beta turn is a sodium ion binding site. It has a high affinity for sodium ions and can coordinate up to three of them. Studies have shown that BQ123 is effective in reversing Ischemia-induced acute renal failure, and it has been suggested that this might be because BQ123 increases reabsorption of sodium ions in the proximal tubule cells.
Leumorphin, also known as dynorphin B1–29, is a naturally occurring endogenous opioid peptide. Derived as a proteolytic cleavage product of residues 226-254 of prodynorphin, leumorphin is a nonacosapeptide and has the sequence Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Gln-Phe-Lys-Val-Val-Thr-Arg-Ser-Gln-Glu-Asp-Pro-Asn-Ala-Tyr-Ser-Gly-Glu-Leu-Phe-Asp-Ala. It can be further reduced to dynorphin B and dynorphin B-14 by pitrilysin metallopeptidase 1, an enzyme of the endopeptidase family. Leumorphin behaves as a potent and selective κ-opioid receptor agonist, similarly to other endogenous opioid peptide derivatives of prodynorphin.
Macitentan, sold under the brand name Opsumit, is an endothelin receptor antagonist (ERA) developed by Actelion and approved for the treatment of pulmonary arterial hypertension (PAH). The other two ERAs marketed as of 2014 are bosentan and ambrisentan. Macitentan is a dual ERA, meaning that it acts as an antagonist of two endothelin (ET) receptor subtypes, ETA and ETB. However, macitentan has a 50-fold increased selectivity for the ETA subtype compared to the ETB subtype. The drug received approval from the U.S. Food and Drug Administration (FDA) on October 13, 2013.
BQ-788 is a selective ETB antagonist.
Streptacidiphilus griseoplanus is a bacterium species from the genus Streptacidiphilus which has been isolated from grassland soil in Iowa in the United States. Streptacidiphilus griseoplanus produces alazopeptin, erythromycin and anticapsin.
Streptomyces halstedii is a bacterium species from the genus of Streptomyces which has been isolated from deeper soil layers. Streptomyces halstedii produces magnamycin B, vicenistatin deltamycin A2, deltamycin A3, bafilomycin B1 and bafilomycin C1. Streptomyces halstedii also produces complex antifungal antibiotics like oligomycins and the antibiotics anisomycin and sinefungin.
Streptomyces olivaceus is a bacterium species from the genus of Streptomyces which has been isolated from soil. Streptomyces olivaceus produces granaticin, elloramycin, tetroazolemycin A and tetroazolemycin B. Streptomyces olivaceus can be used to produce vitamin B12.
Kitasatospora purpeofusca is a bacterium species from the genus Kitasatospora which has been isolated from soil in Japan. Kitasatospora purpeofusca produces negamycin, aestivophoenin A, aestivophoenin B, aestivophoenin C and heptaene.
Paenarthrobacter histidinolovorans is a bacterium species from the genus Paenarthrobacter which has been isolated from soil. Paenarthrobacter histidinolovorans produces histidinol dehydrogenase.
Sarafotoxins (SRTXs) are a group of toxins present in the venom of Atractaspis engaddensis, and in clinical trials cause similar symptoms to patients diagnosed with acute giardiasis. Together with endothelins (ETs), they form a homogenous family of strong vasoconstrictor isopeptides. Among them, a few slightly different substances can be named as SRTX-a, SRTX-b, SRTX-c, which were initially derived from Atractaspis engaddensis. Each one contains twenty-one amino acid residues that spontaneously fold into a defined tertiary structure, with two interchain-cysteine linkages and a long hydrophobic tail. There are also other compounds, however, they are mostly derivations of previously mentioned ones. The main differences in the family of endothelin and sarafotoxins appear at N-terminal of peptides, as C-terminal in all of them is almost the same.
TBPS (tert-butylbicyclophosphorothionate) is a bicyclic phosphate convulsant. It is an extremely potent GABA receptor antagonist.
