et receptor antagonist 1

ET Receptor Antagonist 1 (compound 16h), with an IC50 value of 0.18 nM, is an orally active agent that can be utilized for pulmonary arterial hypertension (PAH) research. It has demonstrated efficacy in mitigating monocrotaline-induced PAH in a rat model [1].

BQ-788 is a selective and potent ETB receptor antagonist with potential hypertensive activity.BQ-788 inhibits ET-1 binding to ETB receptors and inhibits exogenous ET-1-induced elevation of coronary artery perfusion pressure.

Clazosentan (Ro 61-1790) is a selective antagonist of the endothelin A receptor (ETAreceptor) that inhibits ET-1-mediated vasoconstriction, preventing cerebral vasospasm and vasospasm-associated cerebral infarction.

Bosentan (Benzenesulfonamide) is a sulfonamide-derived, competitive and specific endothelin receptor antagonist with a slightly higher affinity for the endothelin A receptor than endothelin B receptor. Bosentan blocks the action of endothelin 1, an extremely potent endogenous vasoconstrictor and bronchoconstrictor, by binding to endothelin A and endothelin B receptors in the endothelium and vascular smooth muscle. Bosentan decreases both pulmonary and systemic vascular resistance and is particularly used in the treatment of pulmonary arterial hypertension.

Unifiram is a nootropic agent.1It increases acetylcholine (ACh) release in the rat cerebral cortexin vivoand induces a long-lasting increase in the amplitude of field excitatory postsynaptic potentials (fEPSPs) in the rat hippocampal CA1 region (EC50= 27 nM). It does not bind to serotonin (5-HT), dopamine, muscarinic, nicotinic, adrenergic, glutamate, histamine, opioid, or GABA receptors at 1 μM. Unifiram (0.1 mg kg) improves memory in non-memory-impaired rats in a social learning test.2It also prevents memory deficits induced by the anticholinergic agent scopolamine, nicotinic receptor antagonist mecamylamine, GABABreceptor agonist baclofen, or α2-adrenergic receptor agonist clonidine in the passive avoidance test in mice when administered at a dose of 0.01 mg kg and prevents memory deficits induced by the AMPA kainate glutamate receptor antagonist NBQX at 0.1 mg kg.1 1.Romanelli, M.N., Galeotti, N., Ghelardini, C., et al.Pharmacological characterization of DM232 (unifiram) and DM235 (sunifiram), new potent cognition enhancersCNS Drug Rev.12(1)39-52(2006) 2.Ghelardini, C., Galeotti, N., Gualtieri, F., et al.The novel nootropic compound DM232 (unifiram) ameliorates memory impairment in mice and ratsDrug Develop. Res.56(1)23-32(2002)

A-192621 is a potent, nonpeptide, orally active, and selective endothelin B (ETB) receptor antagonist with an IC50 of 4.5 nM and a Ki of 8.8 nM. A-192621 promotes apoptosis in PASMCs and elevates both arterial blood pressure and plasma ET-1 levels[1][2][3]. Its selectivity is 636-fold higher for ETB than ETA (IC50 of 4280 nM and Ki of 5600 nM).

J-104132 is a potetn and selective endothelin A B receptor antagonist (Ki: cloned human ETA = 0.034 nM; cloned human ETB = 0.104 nM) . In vitro, J-104132 is a potent antagonist of ET-1-induced accumulation of [3H]inositol phosphates in Chinese hamster ova

Ro 46-2005 is a synthetic non-peptide endothelin receptor antagonist, inhibits the specific binding of 125I-ET-1 to human vascular smooth muscle cells (ETA receptor, IC50: 220 nM).

T-0201 (TA 0201) is a highly potent, long-acting, orally active, and selective ETA receptor antagonist. T-0201 also inhibited ET-1-induced pulmonary artery contraction in isolated rabbits.

α-Conotoxin ImI is a conotoxin that has been found inC. imperialisand has receptor antagonist and anticancer activities.1It is a peptide antagonist of homomeric α7 nicotinic acetylcholine receptors (nAChRs; IC50= 220 nM). α-Conotoxin ImI is selective for α7 nAChRs over α2β2, α3β2, α4β2, α2β4, α3β4, α4β4, and α1β1γδ subunit-containing nAChRs at 5 μM but does inhibit homomeric α9 nAChRs (IC50= 1,800 nM). Administration of paclitaxel in micelles containing α-conotoxin ImI decreases tumor growth in an MCF-7 mouse xenograft model.2Intracerebroventricular, but not intraperitoneal, administration of α-conotoxin ImI (20 nmol/animal) induces seizures in rats.3 1.Johnson, D.S., Martinez, J., Elgoyhen, A.B., et al.α-Conotoxin ImI exhibits subtype-specific nicotinic acetylcholine receptor blockade: Preferential inhibition of homomeric α7 and α9 receptorsMol. Pharmacol.48(2)194-199(1995) 2.Mei, D., Lin, Z., Fu, J., et al.The use of α-conotoxin ImI to actualize the targeted delivery of paclitaxel micelles to α7 nAChR-overexpressing breast cancerBiomaterials4252-65(2015) 3.McIntosh, J.M., Yoshikami, D., Mahe, E., et al.A nicotinic acetylcholine receptor ligand of unique specificity, α-conotoxin ImIJ. Biol. Chem.269(24)16733-16739(1994)

ACT-373898 is a metabolite of the endothelin (ET) receptor type A (ETA) and ETBdual antagonist macitentan .1 1.Dingemanse, J., Sidharta, P.N., Maddrey, W.C., et al.Efficacy, safety and clinical pharmacology of macitentan in comparison to other endothelin receptor antagonists in the treatment of pulmonary arterial hypertensionExpert Opin. Drug Saf.13(3)391-405(2013)

Tritylolmesartan medoxomil is an intermediate in the synthesis of olmesartan medoxomil , a prodrug form of the angiotensin II receptor 1 (AT1) antagonist olmesartan .1 1.Hanumantha Rao, B., Subramanyeswara Rao, I.V., Ravi Kanth, V., et al.A competent and commercially viable process for the synthesis of the anti-hypertensive drug olmesartan medoxomilSci. Pharm.83(3)465-478(2015)

Napyradiomycin A1is a fungal metabolite originally isolated fromC. rubraand has diverse biological activities.1,2It is active againstS. aureus,M. luteus,B. anthracis,C. bovis, andM. smegmatis(MICs = 1.56-12.5 μg/ml).1Napyradiomycin A1is an estrogen receptor antagonist (IC50= 4.2 μM in rat uterine homogenates).2It also inhibits mitochondrial NADH:ubiquinone oxidoreductase (complex I) and succinate:ubiquinone oxidoreductase (complex II) activities in bovine heart homogenates (IC50s = 20 and 9.7 μM, respectively).3 1.Shiomi, K., Iinuma, H., Hamada, M., et al.Novel antibiotics napyradiomycins. Production, isolation, physico-chemical properties and biological activityJ. Antibiot. (Tokyo)39(4)487-493(1986) 2.Hori, Y., Abe, Y., Shigematsu, N., et al.Napyradiomycins A and B1: Non-steroidal estrogen-receptor antagonists produced by a StreptomycesJ. Antibiot. (Tokyo)46(12)1890-1893(1993) 3.Yamamoto, K., Tashiro, E., Motohashi, K., et al.Napyradiomycin A1, an inhibitor of mitochondrial complexes I and IIJ. Antibiot. (Tokyo)65(4)211-214(2012)

Emestrin, a mycotoxin originally isolated from *E. striata*, exhibits antimicrobial, immunomodulatory, and cytotoxic activities. It is effective against fungi *C. albicans* and *C. neoformans*, and bacteria *E. coli*, *S. aureus*, and methicillin-resistant *S. aureus* (MRSA; IC50s = 3.94, 0.6, 2.21, 4.55, and 2.21 μg ml, respectively). Emestrin acts as a chemokine (C-C motif) receptor 2 (CCR2) antagonist (IC50 = 5.4 μM in a radioligand binding assay using isolated human monocytes). At 0.1 μg ml, it induces apoptosis in HL-60 cells and causes necrosis in heart, thymus, and liver tissues in mice at doses of 18-30 mg kg.

Kisspeptin-54 is a peptide ligand of the orphan G protein-coupled receptor GPR54 (Kis = 1.81 and 1.45 nM for rat and human receptors, respectively).1 It is a 54 amino acid peptide encoded by the metastasis suppressor gene KISS-1. Kisspeptin-54 induces calcium mobilization in CHO-K1 cells expressing rat and human receptors (EC50s = 1.39 and 5.47 nM, respectively). It also induces arachidonic acid release in CHO cells expressing rat and human GPR54 in a concentration-dependent manner. Kisspeptin-54 (10-1,000 nM) inhibits insulin secretion from isolated mouse pancreatic β-cells in the presence of 2.8 mM, but not 11.1 mM, glucose.2 Kisspeptin-54 (1-5 nmol, i.c.v.) increases serum levels of luteinizing hormone (LH) and follicular stimulating hormone (FSH) in mice, an effect which is reversed by the gonadotropin releasing hormone (GNRH) antagonist acycline.3References1. Kotani, M., Detheux, M., Vandenbogaerde, A.L., et al. The metastasis suppressor gene KiSS-1 encodes kisspeptins, the natural ligands of the orphan G protein-coupled receptor GPR54. J. Biol. Chem. 276(37), 34631-34636 (2001).2. Vikman, J., and Ahrén, B. Inhibitory effect of kisspeptins on insulin secretion from isolated mouse islets. Diabetes Obes. Metab. 11(Suppl 4), 197-201 (2009).3. Gottsch, M.L., Cunningham, M.J., Smith, J.T., et al. A role for kisspeptins in the regulation of gonadotropin secretion in the mouse. Endocrinology 145(9), 4073-4077 (2004). Kisspeptin-54 is a peptide ligand of the orphan G protein-coupled receptor GPR54 (Kis = 1.81 and 1.45 nM for rat and human receptors, respectively).1 It is a 54 amino acid peptide encoded by the metastasis suppressor gene KISS-1. Kisspeptin-54 induces calcium mobilization in CHO-K1 cells expressing rat and human receptors (EC50s = 1.39 and 5.47 nM, respectively). It also induces arachidonic acid release in CHO cells expressing rat and human GPR54 in a concentration-dependent manner. Kisspeptin-54 (10-1,000 nM) inhibits insulin secretion from isolated mouse pancreatic β-cells in the presence of 2.8 mM, but not 11.1 mM, glucose.2 Kisspeptin-54 (1-5 nmol, i.c.v.) increases serum levels of luteinizing hormone (LH) and follicular stimulating hormone (FSH) in mice, an effect which is reversed by the gonadotropin releasing hormone (GNRH) antagonist acycline.3 References1. Kotani, M., Detheux, M., Vandenbogaerde, A.L., et al. The metastasis suppressor gene KiSS-1 encodes kisspeptins, the natural ligands of the orphan G protein-coupled receptor GPR54. J. Biol. Chem. 276(37), 34631-34636 (2001).2. Vikman, J., and Ahrén, B. Inhibitory effect of kisspeptins on insulin secretion from isolated mouse islets. Diabetes Obes. Metab. 11(Suppl 4), 197-201 (2009).3. Gottsch, M.L., Cunningham, M.J., Smith, J.T., et al. A role for kisspeptins in the regulation of gonadotropin secretion in the mouse. Endocrinology 145(9), 4073-4077 (2004).

PMX-205 is a cyclic hexapeptide that acts as a potent antagonist of C5a receptor (C5aR; IC50= 31 nM).1It is orally active and blocks inflammatory signaling and symptoms in animal models of colitis and allergic asthma.2,3PMX-205 is also brain penetrant and reduces neuroinflammation and neurodegeneration in an animal model of Alzheimer's disease.4 1.March, D.R., Proctor, L.M., Stoermer, M.J., et al.Potent cyclic antagonists of the complement C5a receptor on human polymorphonuclear leukocytes. Relationships between structures and activityMol. Pharmacol.65(4)868-879(2004) 2.Jain, U., Woodruff, T.M., and Stadnyk, A.W.The C5a receptor antagonist PMX205 ameliorates experimentally induced colitis associated with increased IL-4 and IL-10Br. J. Pharmacol.168(2)488-501(2013) 3.Staab, E.B., Sanderson, S.D., Wells, S.M., et al.Treatment with the C5a receptor/CD88 antagonist PMX205 reduces inflammation in a murine model of allergic asthmaInt. Immunopharmacol.21(2)293-300(2014) 4.Fonseca, M.I., Ager, R.R., Chu, S.-H., et al.Treatment with a C5aR antagonist decreases pathology and enhances behavioral performance in murine models of Alzheimer's diseaseJ. Immunol.183(2)1375-1383(2009)

AAA is an antagonist of G protein-coupled receptor 75 (GPR75).1It increases basal GPR75 protein levels and inhibits 20-HETE-induced reductions in GPR75 protein levels in PC3 cells. AAA (5 and 10 μM) also reduces 20-HETE-induced phosphorylation of EGFR, NF-κB, and Akt in, and cell migration of, PC3 cells.In vivo, AAA (10 mg/kg per day) reduces systolic blood pressure, albuminuria, renal angiotensin II levels, and cardiac hypertrophy in a Cyp1a1-Ren-2 transgenic rat model of malignant hypertension when administered prior to induction or after establishment of hypertension.2 1.Cárdenas, S., Colombero, C., Panelo, L., et al.GPR75 receptor mediates 20-HETE-signaling and metastatic features of androgen-insensitive prostate cancer cellsBiochim. Biophys. Acta Mol. Cell Biol. Lipids1865(2)158573(2020) 2.Sedláková, L., Kikerlová, S., Husková, Z., et al.20-Hydroxyeicosatetraenoic acid antagonist attenuates the development of malignant hypertension and reverses it once established: a study in Cyp1a1-Ren-2 transgenic ratsBiosci. Rep.38(5)BSR20171496(2018)

T-5342126 is a toll-like receptor 4 (TLR4) antagonist that reduces LPS-induced production of nitric oxide (NO) in RAW 264.7 cells (IC50 = 27.8 μM) and decreases LPS-induced IL-8, TNF-α, and IL-6 production in isolated human whole blood (IC50s = 110.5, 315.6, and 318.4 μM, respectively). T-5342126 (82 mg kg) also reduces ethanol intake and the abundance of ionized calcium-binding adapter molecule 1 (Iba1), a marker of microglial activation, in the central nucleus of the amygdala in ethanol-dependent mice.

Nebentan (YM598) is a potent, selective and orally active non-peptide endothelin ETA receptor antagonist through the modification of Bosentan . Nebentan inhibits [125I] endothelin-1 binding to cloned human endothelin ETA and ETB receptor, with Ki of 0.697 nM and 569 nM, respectively[1]. YM598 can ameliorate the progression of cor pulmonale and myocardial infarction in vivo[2]. Nebentan inhibits the specific binding of [125I] endothelin-1 to endothelin ETA and ETB receptors in a concentration dependent manner,Ki values are 0.697 nM and 1.53 nM for human and rat endothelin ETA receptors, respectively. In contrast, YM598 exhibits low affinities for human and rat endothelin ETB receptors, with Ki values of 569 nM and 155 nM,respectively[1].In measurement of intracellular Ca2+ concentration, Nebentan concentration-dependently inhibits the increase in [Ca2+]i induced by 10 nM endothelin-1 in both CHO cells and A10 cells, the IC50 values are 26.2 nM for CHO cells and 26.7 nM for A10 cells, respectively[1]. Nebentan (oral administration; 0.1-1 mg kg; 4 weeks) significantly inhibits the progression of pulmonary hypertension and the development of right ventricular hypertrophy[2].Nebentan (oral administration; 1 mg kg; 30 weeks) significantly ameliorates the poor survival rate of CHF rats, it markedly reduces the hypertrophy of both ventricles as well as pulmonary congestion[2]. [1]. Hironori Yuyama, et al. Pharmacological Characterization of YM598, an Orally Active and Highly Potent Selective Endothelin ET(A) Receptor Antagonist. Eur J Pharmacol. 2003 Sep 30;478(1):61-71. [2]. Akira Fujimori, et al. YM598, an Orally Active ET(A) Receptor Antagonist, Ameliorates the Progression of Cardiopulmonary Changes and Both-Side Heart Failure in Rats With Cor Pulmonale and Myocardial Infarction. J Cardiovasc Pharmacol. 2004 Nov;44 Suppl 1:S354-7.

Skyrin is a fungal metabolite characterized by a bisanthraquinone structure. It interferes with glucagon signaling through adenylate cyclase without binding to the glucagon receptor. At 10 μM, skyrin reduces both glucagon-stimulated cAMP production and glycogenolysis. It does not interfere with epinephrine or glucagon-like peptide 1 effects on these parameters.[1] Reference:[1]. Parker, J.C., McPherson, R.K., Andrews, K.M., et al. Effects of skyrin, a receptor-selective glucagon antagonist, in rat and human hepatocytes. Diabetes 49, 2079-2086 (2012).

Echistatin TFA, the smallest active RGD protein from snake venoms, is a potent inhibitor of platelet aggregation, bone resorption in culture, and an antagonist of αIIbβ3, αvβ3, and α5β1[1][2][3][4].

Naloxegol (NKTR-118; AZ-13337019) is an opioid receptor antagonist[1].

SB-612111 is a novel and potent human opiate receptor-like orphan receptor (ORL-1) antagonist with a high affinity for hORL-1 (Ki = 0.33 nM). It exhibits selectivity for μ-, κ-, and δ-receptors with Ki values of 57.6 nM, 160.5 nM, and 2109 nM, respectively. SB-612111 effectively antagonizes the pronociceptive action of Nociceptin in an acute pain model[1].

Bile acids are essential for solubilization and transport of dietary lipids, are the major products of cholesterol catabolism, and are physiological ligands for farnesoid X receptor (FXR), a nuclear receptor that regulates genes involved in lipid metabolism.1They are also inherently cytotoxic, as physiological imbalance contributes to increased oxidative stress.2,3Bile acid-controlled signaling pathways are promising novel targets to treat such metabolic diseases as obesity, type II diabetes, hyperlipidemia, and atherosclerosis.Guggulsterone, derived from resin of the guggul tree, is a competitive antagonist of FXR bothin vitroandin vivo.4Thecisstereoisomer of guggulsterone, (E)-guggulsterone, decreases chenodeoxycholic acid (CDCA)-induced FXR activation with an IC50value of 15 μM.5,6By inhibiting CDCA-induced transactivation of FXR, guggulsterone lowers low-density lipoprotein cholesterol and triglyceride levels in rodents fed a high cholesterol diet.4 1.Makishima, M., Okamoto, A.Y., Repa, J.J., et al.Identification of a nuclear receptor for bile acidsScience2841362-1365(1999) 2.Barbier, O., Torra, I.P., Sirvent, A., et al.FXR induces the UGT2B4 enzyme in hepatocytes: A potential mechanism of negative feedback control of FXR activityGastroenterology1241926-1940(2003) 3.Tan, K.P., Yang, M., and Ito, S.Activation of nuclear factor (erythroid-2 like) factor 2 by toxic bile acids provokes adaptive defense responses to enhance cell survival at the emergence of oxidative stressMol. Pharmacol.72(5)1380-1390(2007) 4.Urizar, N.L., Liverman, A.B., Dodds, D.T., et al.A natural product that lowers cholesterol as an anatagonist ligand for FXRScience296(5573)1703-1706(2002) 5.Cui, J., Huang, L., Zhao, A., et al.Guggulsterone is a farnesoid X receptor antagonist in coactivator association assays but acts to enhance transcription of bile salt export pumpThe Journal of Biological Chemisty278(12)10214-10220(2003) 6.Wu, J., Xia, C., Meier, J., et al.The hypolipidemic natural product guggulsterone acts as an antagonist of the bile acid receptorMolecular Endocrinology16(7)1590-1597(2002)