radioligand

Sigma-2 Radioligand 1 (compound 1) serves as a selective Sigma-2 ligand, demonstrating favorable biodistribution in mice and robust in vivo activity in rats. The [18F] modified version of Sigma-2 Radioligand 1 enhances the visualization of tumors in micro-PET CT imaging by providing high tumor uptake and an impressive tumor-to-background ratio. Additionally, experiments confirm that this compound binds with high specificity to U87MG glioma xenografts [1].

CB2 PET Radioligand 1 (compound [18F]9) is a positron emission tomography (PET) radioligand with high affinity for the human cannabinoid receptor 2 (hCB2, Ki=7.7 nM). It is synthesized via Cu-mediated 18F-fluorination and demonstrates significant brain uptake in a mouse model of neuroinflammation [1].

MRS 1754 is a selective antagonist radioligand for the A2B adenosine receptor, exhibiting very low affinity for A1 and A3 receptors in both humans and rats.

Arotinolol hydrochloride（Arotinolol HCl） is a non-selective α β-adrenergic receptor blocker.Arotinolol hydrochloride inhibits the binding of the radioligand 125I-ICYP to the 5HT1B-hydroxytryptamine receptor. Arotinolol hydrochloride is an antihypertensive and anti-obesity agent that improves aortic stiffness in rats and is used to study obesity-related diseases.

(S)-Desmethyl-NNC112 ((+)-Desmethyl-NNC112) is a selective PET radioligand that binds to D-dopamine receptors.

Lusaperidone (R107474) is a potent α2-adrenergic receptor antagonist, a potential radioligand for the α (2)-adrenergic receptor, with inhibitory effects on α2A and α2C, with Ki values of 0.13 and 0.15 nM, respectively.

3-aminopropylphosphonic acid (3-APPA) is a phosphonic analog of GABA that acts as a partial agonist of GABAB receptors (IC50 = 1.5 μM in a radioligand binding assay).

FAUC-365 is a D3 dopamine receptor agonist.

PAR2 (1-6) amide is a synthetic peptide agonist of proteinase-activated receptor 2 (PAR2) that corresponds to residues 1-6 of the amino terminal tethered ligand sequence of human PAR2 and residues 37-42 of the full-length sequence.1It binds to NCTC 2544 cells expressing human PAR2 (Ki= 9.64 μM in a radioligand binding assay) and induces calcium mobilization in the same cells (EC50= 0.075 μM).2PAR2 (1-6) amide (100 μM) reduces colony formation of A549 lung cancer cells.1It induces superoxide production and degranulation in isolated human eosinophils when used at a concentration of 500 μM.3PAR2 (1-6) amide (5 μmol/kg) induces tear secretion in rats when used in combination with amastatin .4 1.Bohm, S.K., Kong, W., Bromme, D., et al.Molecular cloning, expression and potential functions of the human proteinase-activated receptor-2Biochem. J.314(Pt 3)1009-1016(1996) 2.Kanke, T., Ishiwata, H., Kabeya, M., et al.Binding of a highly potent protease-activated receptor-2 (PAR2) activating peptide, [3H]2-furoyl-LIGRL-NH2, to human PAR2Br. J. Pharmacol.145(2)255-263(2005) 3.Miike, S., McWilliam, A.S., and Kita, H.Trypsin induces activation and inflammatory mediator release from human eosinophils through protease-activated receptor-2J. Immunol.167(11)6615-6622(2001) 4.Nishikawa, H., Kawai, K., Tanaka, M., et al.Protease-activated receptor-2 (PAR-2)-related peptides induce tear secretion in rats: Involvement of PAR-2 and non-PAR-2 mechanismsJ. Pharmacol. Exp. Ther.312(2)324-331(2005)

Leucomycin A13 is a macrolide antibiotic and a component of the leucomycin complex originally isolated from S. kitasatoensis. It is active against B. subtilis, S. aureus, M. luteus, and E. coli with MIC values of 0.16, 0.16, 0.08, and >10 μg ml, respectively. It binds to ribosomes with an IC50 value of 1.2 μM in a radioligand binding assay.

N-(1-(3,4-Dihydroxyphenyl)propan-2-yl)oleamide binds to the cannabinoid 1 (CB1) receptor with a Ki value of 365 nM in a radioligand binding assay using rat brain homogenate. It has an EC50 value of 698 nM for the peroxisome proliferator-activated receptor α (PPARα) in a luciferase reporter assay and, in rats, it decreases food intake. It does not inhibit fatty acid amide hydrolase (FAAH).

Altanserin can binds to the 5-HT2A receptor. Labeled with the isotope fluorine-18 it is used as a radioligand in positron emission tomography (PET) studies of the brain.

Deltorphin II is a peptide agonist of δ2-opioid receptors.1,2It is selective for δ-opioid receptors over μ- and κ-opioid receptors in radioligand bindings assays (Kis = 0.0033, >1, and >1 μM, respectively) and induces [35S]GTPγS binding in mouse brain membrane preparations (EC50= 0.034 μM). Deltorphin II (0.12 mg/kg) decreases the infarction zone:risk zone ratio in a rat model of myocardial ischemia-reperfusion injury induced by coronary occlusion, an effect that can be reversed by the δ2-opioid receptor antagonist naltriben but not the δ1-opioid receptor antagonist BNTX.3Intrathecal administration of deltorphin II (15 μg/animal) increases latency to withdraw in the paw pressure and tail-flick tests in rats.4 1.Raynor, K., Kong, H., Chen, Y., et al.Pharmacological characterization of the cloned κ-, δ-, and μ-opioid receptorsMol. Pharm.45(2)330-334(1994) 2.Scherrer, G., Befort, K., Contet, C., et al.The delta agonists DPDPE and deltorphin II recruit predominantly mu receptors to produce thermal analgesia: A parallel study of mu, delta and combinatorial opioid receptor knockout miceEur. J. Neurosci.19(8)2239-2248(2004) 3.Maslov, L.N., Barzakh, E.I., Krylatov, A.V., et al.Opioid peptide deltorphin II simulates the cardioprotective effect of ischemic preconditioning: role of δ2-opioid receptors, protein kinase C, and KATP channelsBull. Exp. Biol. Med.149(5)591-593(2010) 4.Labuz, D., Toth, G., Machelska, H., et al.Antinociceptive effects of isoleucine derivatives of deltorphin I and deltorphin II in rat spinal cord: A search for selectivity of delta receptor subtypesNeuropeptides32(6)511-517(1998)

ORM-13070 is a selective antagonist radioligand for the α2C adrenoceptor subtype. ORM-13070 C-11 is under investigation in clinical trial.

GSK-215083 is a PET radioligand for the 5-HT6 receptor. GSK 215083 is a quinoline based compounds and acts by antagonising the 5-HT6 receptor. GSK-215083 binds to receptors 5-hydroxytrypamine-6 (5HT6) in the striatum and 5-hydroxytryptamine-2A (5HT2A) in

Mefway F-18 is a PET radioligand specific to serotonin-1A receptors.

AZD-2184 is a radioligand for detecting beta-amyloid deposits.

SB 224289 is a selective antagonist of 5-HT1B receptor with pKi of 8.2. It is a centrally active following oral administration in vivo. SB 224289 displays 60-fold selectivity over 5-HT1D, 5-HT1A, 5-HT1E, 5-HT1F, 5-HT2A and 5-HT2C receptors in radioligand

RBP4 ligand-1 is a non-retinoid ligand for retinol-binding protein 4 (RBP4). It exhibits hRBP4SPA IC50 and RBP4-TTR FRET IC50 values of 0.23±0.11 μM and 0.13±0.12 μM, respectively, in radioligand binding and FRET assays. The measured concentration was 0.12 μM.

Taurolithocholic Acid-d5 Sodium Salt (Major) is a deuterated compound of Taurolithocholic Acid Sodium Salt. Taurolithocholic Acid Sodium Salt has a CAS number of 6042-32-6. The major human metabolite, a bile acid which inhibits radioligand binding to muscarinic M1, but not to M2 or M3 receptors.

Atomoxetine-d3 hydrochloride, the deuterium-labeled form of Atomoxetine hydrochloride, acts as a potent and selective noradrenalin re-uptake inhibitor with Ki values of 5, 77, and 1451 nM for the inhibition of radioligand binding to human NET, SERT, and DAT, respectively [1] [2].

STING18 is a competitive ligand of stimulator of interferon genes (STING; IC50 = 0.068 μM in a radioligand binding assay).1 It inhibits cGAMP-induced IFN-β production (IC50 = 11 μM) but does not stimulate IFN-β production (EC50 = >30 μM) in THP-1 cells. |1. Siu, T., Altman, M.D., Baltus, G.A., et al. Discovery of a novel cGAMP competitive ligand of the inactive form of STING. Med. Chem. Lett. 10(1), 92-97 (2019).

ER176 is a novel PET radioligand utilized for the visualization of 18 kDa translocator protein (TSPO), a neuroinflammation biomarker, marking the advancement in imaging technology.

Fuscin is a quinonoid fungal metabolite originally isolated from O. fuscum that has diverse biological activities. It inhibits binding of the ADP/ATP translocase inhibitor atractyloside to rat liver mitochondria in an ADP-dependent manner when used at a concentration of 50 μM in a radioligand binding assay. Fuscin (20 μM) reduces the glutathione content of rat liver mitochondria to 28% of controls and inhibits NADH oxidation in sonicated pigeon heart mitochondria preparations in a concentration-dependent manner. It competes with macrophage inflammatory protein 1α (MIP-1α) for binding to CCR5 chemokine receptors in vitro with an IC50 value of 21 μM.

Taurolithocholic acid sodium salt (Sodium taurolithocholate) is the major human metabolite, a bile acid which inhibits radioligand binding to muscarinic M1, but not to M2 or M3 receptors.

SP203 is a radioligand for brain metabotropic glutamate receptor imaging.

NBI-42902 is a potent inhibitor of peptide radioligand binding to the human GnRH receptor (K(i) = 0.56 nm). Tritiated NBI-42902 binds with high affinity (K(d) = 0.19 nm) to a single class of binding sites and can be displaced by a range of peptide and nonpeptide GnRH receptor ligands. In vitro experiments demonstrate that NBI-42902 is a potent functional, competitive antagonist of GnRH stimulated IP accumulation, Ca(2+) flux, and ERK1/2 activation. It did not stimulate histamine release from rat peritoneal mast cells. Finally, it is effective in lowering serum LH in castrated male macaques after oral administration. Overall, these data provide a benchmark of pharmacological characteristics required for a nonpeptide GnRH antagonist to effectively suppress gonadotropins in humans and suggest that NBI-42902 may have clinical utility as an oral agent for suppression of the hypothalamic-pituitary-gonadal axis. (source: Endocrinology. 2007 Feb;148(2):857-67. Epub 2006 Nov 9.)

PK14105 has been evaluated biologically as a potential radioligand for positron emission tomography (PET) studies targeting peripheral benzodiazepine binding sites (PBBS) receptors. When administered to rats with unilaterally lesioned striata, PK14105 was observed to quickly cross the blood-brain barrier, displaying significant radioactivity retention in the lesioned striatum, in contrast to the unlesioned striatum or cerebellar vermis. Additionally, PK14105 has the capability to inhibit receptor ligands, calcium channel ligands, and co-transporters in all salivary glands.

Altanserin tartrate is a compound that binds to the 5-HT2A receptor. Labeled with the isotope fluorine-18 it is used as a radioligand in positron emission tomography (PET) studies of the brain.

PF-06455943, a leucine rich repeat kinase 2 (LRRK2) inhibitor, exhibits an inhibition concentration (IC50) value of 3 nM and also functions as a PET radioligand. It is utilized in the research of ADME/neuro PK characterization and Parkinson's disease (PD).

PSMA-IN-3 (compound 17) is a novel, high-affinity inhibitor of Prostate-Specific Membrane Antigen (PSMA) with an IC50 of 13 nM, showing potential for development as an 18F-labeled radioligand for PET imaging of PSMA in prostate cancer [1].

CELT-133 is a selective fluorescent antagonist for the hα1A adrenergic receptor, demonstrating complete selectivity towards α1A over α2A receptors, with a Ki of 5 nM and 15% displacement at 1 μM in radioligand binding assays, respectively. It displays equivalent affinity across all α1 adrenergic receptor subtypes. Notably, CELT-133 features excitation and emission maxima (λ) at 560 and 571 nm, respectively, making it suitable for use as an acceptor dye in time-resolved Förster resonance energy transfer (TR-FRET) assays when paired with the CoraFluor 1 TR-FRET donor.

CELT-426 is a potent, partially selective fluorescent antagonist of the human D2 dopamine receptor, exhibiting Ki values of 89.3 nM, 194.8 nM, and 263.6 nM for D2, D3, and D4 dopamine receptors, respectively, in radioligand binding assays. This compound serves as an effective fluorescent probe for dopamine receptors, facilitating its application in a range of techniques including fluorescence binding assays, live cell imaging, flow cytometry, and fluorescence polarization assays. It provides an alternative to GPCR radiolabeling ligands. CELT-426 possesses excitation and emission maxima (λ) of 560 nm and 571 nm, respectively, making it suitable for use as an acceptor dye in Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) assays in conjunction with the CoraFluor1 TR-FRET donor.

Selective prostacyclin IP receptor antagonist (pKi = 8.3). Exhibits no affinity at other prostanoid receptors (EP1-4, FP and TP) in a radioligand binding assay. Demonstrates analgesic activity in rats. Orally bioavailable. Clark et al (2004) Discovery and SAR development of 2-(phenylamino) imidazolines as prostacyclin receptor antagonists. Bioorg.Med.Chem.Lett. 14 1053 PMID:15013022 |Jones et al (2006) Investigation of the prostacyclin (IP) receptor antagonist RO1138452 on isolated blood vessel and platelet preparations. Br.J.Pharmacol. 149 110 PMID:16880763 |Bley et al (2006) RO1138452 and RO3244794: characterization of structurally distinct, potent and selective IP (prostacyclin) receptor antagonists. Br.J.Pharmacol. 147 335 PMID:16331286

11-trans Leukotriene C4 (11-trans LTC4) is a C-11 double bond isomer of LTC4. LTC4 undergoes slow temperature-dependent isomerization to 11-trans LTC4 during storage. 11-trans LTC4 is produced in smaller amounts relative to LTC4 in ionophore-stimulated HMC-1 cells (a human mast cell line) and equine eosinophils, but not in human neutrophils or RBL-1 cells. It is nearly equipotent with LTC4 for contraction of guinea pig parenchymal and ileum. In a radioligand binding assay using guinea pig ileum as a cysteinyl leukotriene receptor preparation, the pKis for LTC4 and 11-trans LTC4 were determined to be 6.42 and 6.58, respectively.

Methylatropine is an antagonist of muscarinic acetylcholine receptors (IC50= <0.1 nM in a radioligand binding assay using isolated porcine brain membranes) and a derivative of atropine .1,2It reduces acetylcholine-induced decreases in blood pressure in rats when administered intravenously with an ED50value of 5.5 μg/kg.2Methylatropine reduces salivation, induces mydriasis, and increases heart rate in dogs.3 1.Schmeller, T., Sporer, F., Sauerwein, M., et al.Binding of tropane alkaloids to nicotinic and muscarinic acetylcholine receptorsPharmazie50(7)493-495(1995) 2.Brezenoff, H.E., Xiao, Y.-F., and Vargas, H.A comparison of the central and peripheral antimuscarinic effects of atropine and methylatropine injected systemically and into the cerebral ventriclesLife Sci.42(8)905-911(1988) 3.Albanus, L.Central and peripheral effects of anticholinergic compoundsActa Pharmacol. Toxicol. (Copenh)28(4)305-326(1970)

Highly potent and selective group II metabotropic glutamate receptor antagonist. Disodium salt of LY 341495 Fitzjohn et al (1998) The potent mGlu receptor antagonist LY341495 identifies roles for both cloned and novel mGlu receptors in hippocampal synaptic plasticity. Neuropharmacology 37 1445 PMID:9886667 |Ornstein et al (1998) 2-Substituted (2SR)-2-amino-2-((1SR,2SR)-2-carboxycycloprop-1-yl) glycines as potent and selective antagonists of group II metabotropic glutamate receptors. 2. Effects of aromatic substitution, pharmacological characterization, and bioav J.Med.Chem. 41 358 PMID:9464367 |Johnson et al (1999) [3H]-LY341495 as a novel antagonist radioligand for group II metabotropic glutamate receptors: characterization of binding to membranes of mGlu receptor subtype expressing cells. Neuropharmacology 38 1519 PMID:10530814

Reduced haloperidol is an active metabolite of haloperidol . It is formed via reduction of haloperidol by ketone reductase. Reduced haloperidol inhibits radioligand binding to sigma-1 and dopamine D2 receptors (Kis = 1.4 and 31 nM, respectively) and stimulates brain-derived neurotrophic factor (BDNF) secretion from CCF-SSTG1 and U87MG astrocytic glial cells. It also inhibits norepinephrine, dopamine, and serotonin (5-HT) reuptake (Kis = 21, 25, and 33 μM, respectively, in COS-7 cells expressing the human transporters). Reduced haloperidol (0.5 mg/kg) increases latency to paw withdrawal in mouse models of capsaicin- but not force-induced mechanical hypersensitivity.

5-hydroxy-Nω-methyl Tryptamine is a metabolite of serotonin in humans that has also been found in plants. It is an agonist of the 5-HT receptor subtype 5-HT7 (IC50 = 23 pM in a radioligand binding assay). 5-hydroxy-Nω-methyl Tryptamine increases intracellular cyclic AMP production in HEK293 cells expressing 5-HT7 (EC50 = 22 nM). It inhibits serotonin uptake in HEK293 cells expressing human serotonin transporters (IC50 = 490 nM). Elevated levels of urinary 5-hydroxy-Nω-methyl tryptamine have been found in patients with schizophrenia, depression, and epilepsy.

Flutafuranol, also known as AZD 4694 and NAV4694, is a bio-active chemical. AZD4694 shows high affinity for beta-amyloid fibrils in vitro (K(d) = 2.3 +/- 0.3 nM). The fluorine-18 labeled AZD4694 may have potential for PET-visualization of cerebral beta-am

MLi-2 is a structurally novel, highly potent, and selective LRRK2 kinase inhibitor with central nervous system activity. MLi-2 exhibits exceptional potency in a purified LRRK2 kinase assay in vitro (IC50 = 0.76 nM), a cellular assay monitoring dephosphorylation of LRRK2 pSer935 LRRK2 (IC50 = 1.4 nM), and a radioligand competition binding assay (IC50 = 3.4 nM).

PD 140376 is a highly selective antagonist radioligand for the cholecystokinin(B)-gastrin receptor in guinea pig gastric mucosa & cerebral cortex in the peripheral and central nervous systems.

Guanfacine-13C,15N3is intended for us as an internal standard for the quantification of guanfacine by GC- or LC-MS. Guanfacine is an α2-adrenergic receptor (α2-AR) agonist with Kivalues of 93, 1,380, and 3,890 nM for α2A-, α2B-, and α2C-ARs, respectively, in a radioligand binding assay.1It has EC50values of 52, 288, and 602 nM for α2A-, α2B-, and α2C-ARs, respectively, for stimulated [35S]GTPγS binding. It also binds to imidazoline receptor 1 (Ki= 19 nM in a radioligand binding assay).2Guanfacine (0.3-5 mg/kg) binds to adrenergic receptors in the central nervous system and lowers blood pressure in hypertensive rats in a dose-dependent manner.3It also improves spatial working memory deficits induced by hypobaric hypoxia in rats.4Formulations containing guanfacine are used in the treatment of high blood pressure and attention deficit hyperactivity disorder (ADHD). 1.Jasper, J.R., Lesnick, J.D., Chang, L.K., et al.Ligand efficacy and potency at recombinant α2 adrenergic receptors: Agonist-mediated [35S]GTPγS bindingBiochem. Pharmacol.55(7)1035-1043(1998) 2.Nikolic, K., Filipic, S., and Agbaba, D.QSAR study of imidazoline antihypertensive drugsBioorg. Med. Chem.16(15)7134-7140(2008) 3.Scholtysik, G.Pharmacology of guanfacineBr. J. Clin. Pharmacol.10(Suppl 1)21S-24S(1980) 4.Kauser, H., Sahu, S., Kumar, S., et al.Guanfacine is an effective countermeasure for hypobaric hypoxia-induced cognitive declineNeuroscience254110-119(2013)

AH-9700 free base is use for treatment of urge incontinence and pollakiuria.In a radioligand binding study,AH-9700 free base showed high affinities for sigma receptors and it produces a marked inhibitory effect on the micturition reflex (i.e. bladder capacity-increasing effect) in experimental animals with normal bladder functions.

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.

UCB-J is a radioligand for the synaptic vesicle protein 2A (SV2A), utilized in positron emission tomography (PET)[4].

TRV-7019 is a butyrylcholinesterase-targeting radioligand capable of penetrating the blood-brain barrier (BBB) for brain imaging. It is utilized for diagnosing conditions such as amyloid diseases, multiple sclerosis, brain tumors, or to assess butyrylcholinesterase activity [1].

GSK931145 is a positron emission tomography (PET) radioligand, it is suitable for quantifying glycine transporter (GlyT1) availability in the living brain.

PAR2 (1-6) is a synthetic peptide agonist of proteinase-activated receptor 2 (PAR2) that corresponds to residues 1-6 of the amino terminal tethered ligand sequence of mouse and rat PAR2. It also corresponds to residues 39-44 and 37-42 of the mouse and rat full-length sequences, respectively. PAR2 (1-6) induces relaxation in precontracted rat arteries in a concentration-dependent manner, an effect that can be reduced by the nitric oxide synthase inhibitor L-NNA . It inhibits keratinocyte growth in the presence and absence of growth factors. PAR2 (1-6) inhibits LPS-induced pulmonary neutrophil influx and increases in matrix metalloproteinase-2 (MMP-2) activity in mice.