ONO-8590580 is a novel and potent GABAAα5 negative allosteric modulator which enhances long-term potentiation and improves cognitive deficits in preclinical models. ONO-8590580 binds to the benzodiazepine binding sites on recombinant human α5-containing GABAA receptors with a Ki of 7.9 nM, and showed functionally selective GABAAα5 NAM activity for GABA-induced Cl- channel activity with a maximum 44.4% inhibition and an EC50 of 1.1 nM. In rat hippocampal slices, tetanus-induced long-term potentiation of CA1 synapse response was significantly augmented in the presence of 300 nM ONO-8590580. Orally administered ONO-8590580 (1-20 mg/kg) dose-dependently occupied hippocampal GABAAα5 in a range of 40%-90% at 1 hour after intake. In the rat passive avoidance test, ONO-8590580 (3-20 mg/kg, by mouth) significantly prevented (+)-MK-801 hydrogen maleate (MK-801)-induced memory deficit. In addition, ONO-8590580 (20 mg/kg, p.o.) was also effective in improving the cognitive deficit induced by scopolamine and MK-801 in the rat eight-arm radial maze test with equal or greater activity than 0.5 mg/kg donepezil. No anxiogenic-like or proconvulsant effect was associated with ONO-8590580 at 20 mg/kg p.o. in the elevated plus maze test or pentylenetetrazole-induced seizure test, respectively. In sum, ONO-8590580 is a novel GABAAα5 NAM that enhances hippocampal memory function without an anxiogenic or proconvulsant risk.
Physicochemical Properties
| Molecular Formula | C21H21FN6 |
| Molecular Weight | 376.430046796799 |
| Exact Mass | 376.181 |
| CAS # | 1802661-73-9 |
| PubChem CID | 118278442 |
| Appearance | White to off-white solid powder |
| LogP | 3.1 |
| Hydrogen Bond Donor Count | 1 |
| Hydrogen Bond Acceptor Count | 5 |
| Rotatable Bond Count | 5 |
| Heavy Atom Count | 28 |
| Complexity | 545 |
| Defined Atom Stereocenter Count | 0 |
| SMILES | FC1C(C)=C2N=CN(C2=CC=1NC1C=CC(C2=CN(C)C=N2)=CN=1)CC1CC1 |
| InChi Key | INGJMHPGMVUEKY-UHFFFAOYSA-N |
| InChi Code | InChI=1S/C21H21FN6/c1-13-20(22)16(7-18-21(13)25-12-28(18)9-14-3-4-14)26-19-6-5-15(8-23-19)17-10-27(2)11-24-17/h5-8,10-12,14H,3-4,9H2,1-2H3,(H,23,26) |
| Chemical Name | 1-(Cyclopropylmethyl)-5-fluoro-4-methyl-N-(5-(1-methyl-1H-imidazol-4-yl)pyridin-2-yl)-1H-benzo[d]imidazol-6-amine |
| Synonyms | ONO8590580; ONO 8590580; ONO-8590580 |
| HS Tariff Code | 2934.99.9001 |
| Storage |
Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition | Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs) |
Biological Activity
| Targets |
GABAA receptor containing α5 subunit (GABAA α5; Ki = 7.9 nM) GABAA receptor containing α1 subunit (GABAA α1; Ki = 140 nM) GABAA receptor containing α2 subunit (GABAA α2; Ki = 32 nM) GABAA receptor containing α3 subunit (GABAA α3; Ki = 24 nM)[1] |
| ln Vitro |
ONO-8590580 concentration-dependently inhibited GABA-induced chloride currents in HEK293 cells expressing human GABAA α5β3γ2 receptors, with a maximum inhibition of 44.4% and an EC50 of 1.1 nM. It showed minimal or no effect on currents mediated by GABAA α1, α2, or α3 subtypes under the same conditions.[1] In rat hippocampal brain slices, application of 300 nM ONO-8590580 significantly enhanced and prolonged long-term potentiation (LTP) induced by a θ-burst protocol in the CA1 region, compared to control slices.[1] |
| ln Vivo |
The effect of ONO-8590580 on MK-801/scopolamine-induced cognitive impairments in the 8-arm radial maze test was examined. The dosages of MK-801 and scopolamine in this trial were 0.075 mg/kg (ip) and 0.2 mg/kg (ip), respectively. ONO-8590580 (20 mg/kg, po) significantly reduced the number of mistakes and total delay compared to control. In the current study, ONO-8590580, but not donepezil, considerably reduced the number of errors, which may imply that ONO-8590580 may be more successful in the treatment of AD patients. The observations showing that ONO-8590580 does not have anxiogenic or proconvulsant effects are compatible with the behavioral phenotype of α5-/- mice [1]. ONO-8590580 (1, 3, 10, 20 mg/kg) dose-dependently occupied hippocampal GABAA α5 receptors in rats, with occupancies of 44%, 53%, 71%, and 89% respectively, measured 1 hour after administration (ED50 = 1.9 mg/kg).[1] In the rat passive avoidance test, ONO-8590580 (3, 10, 20 mg/kg, p.o.) significantly reversed the memory impairment induced by MK-801.[1] In the rat 8-arm radial maze test, ONO-8590580 (20 mg/kg, p.o.) significantly improved the cognitive deficits induced by co-administration of scopolamine and MK-801, reducing both the number of errors and the total latency to complete the task. Its effect on error reduction was superior to that of 0.5 mg/kg donepezil.[1] ONO-8590580 (20 mg/kg, p.o.) did not show anxiogenic-like effects in the rat elevated plus maze test, unlike the non-selective GABAA NAM FG-7142.[1] ONO-8590580 (10 mg/kg, i.p.) did not show proconvulsant effects in the mouse pentylenetetrazole (PTZ) seizure threshold test, unlike FG-7142.[1] |
| Enzyme Assay |
The binding affinity of ONO-8590580 for human recombinant GABAA receptors was determined using a scintillation proximity assay (SPA). Membranes from HEK293 cells stably expressing human GABAA α1β3γ2, α2β3γ2, α3β3γ2, or α5β3γ2 receptors were prepared. For the assay, test compounds, membrane protein, and PVT-WGA beads were added to a 384-well plate and pre-incubated. The reaction was initiated by adding the radioligand: [³H]Ro15-1788 for α1, α2, α3 subtypes or [³H]Ro15-4513 for the α5 subtype. After incubation, plates were centrifuged and radioactivity was measured. Inhibition constants (Ki) were calculated from the obtained EC50 values using the Cheng-Prusoff equation and known Kd values for the radioligands.[1] |
| Cell Assay |
The functional efficacy of ONO-8590580 on human GABAA receptor subtypes was assessed using whole-cell patch-clamp electrophysiology on HEK293 cells stably expressing α1β3γ2, α2β3γ2, α3β3γ2, or α5β3γ2. Cells were dissociated, recovered, and suspended in an extracellular solution. Currents were recorded at a holding potential of -60 mV. Control GABA responses were first established at their respective EC20 concentrations. Test compounds were pre-applied for 1 minute before co-application with the EC20 concentration of GABA. The effect of ONO-8590580 on GABA-induced chloride currents was measured.[1] |
| Animal Protocol |
For in vivo receptor occupancy studies in rats, ONO-8590580 was formulated by first dissolving in DMSO, then adding to a solubilizing agent and water (final composition: 2% DMSO, 20% solubilizing agent, 78% water). It was administered orally 1 hour before sacrifice. The radioligand [³H]Ro15-4513 was administered intravenously 10 minutes before sacrifice to measure GABAA α5 occupancy.[1] In the rat passive avoidance test, ONO-8590580 or vehicle was administered orally 1 hour before both the acquisition and retention trials. MK-801 or saline was administered intraperitoneally 30 minutes before the acquisition trial.[1] In the rat 8-arm radial maze test, ONO-8590580, donepezil, or vehicle was administered orally 1 hour before the test trial. MK-801 and scopolamine were administered subcutaneously 0.5 hours before the test trial.[1] In the rat elevated plus maze test, ONO-8590580 (20 mg/kg) or vehicle was administered orally, and FG-7142 (15 mg/kg) was administered intraperitoneally, 1 hour before the 5-minute test.[1] In the mouse PTZ proconvulsant test, ONO-8590580 (10 mg/kg), FG-7142 (10 mg/kg), or vehicle was administered intraperitoneally 30 minutes before intravenous infusion of PTZ solution.[1] |
| References |
[1]. ONO-8590580, a Novel GABAAα5 Negative Allosteric Modulator Enhances Long-Term Potentiation and Improves Cognitive Deficits in Preclinical Models. J Pharmacol Exp Ther. 2018 Jul;366(1):58-65. |
| Additional Infomation |
ONO-8590580 is a novel, orally available, and functionally selective negative allosteric modulator (NAM) of the GABAA receptor α5 subunit. GABAA α5 receptors are highly expressed in the hippocampus and are implicated in tonic inhibition that can suppress neuronal excitability and memory formation. Inhibiting these receptors is a proposed strategy for cognitive enhancement. The compound was developed for potential use in cognitive disorders like Alzheimer's disease. It shows a promising profile by enhancing synaptic plasticity (LTP) and improving memory in rodent models without the anxiogenic or proconvulsant side effects typically associated with non-selective GABAA NAMs.[1] Reactive astrocytes in Alzheimer's disease may release GABA, activating extrasynaptic GABAA α5 receptors. Therefore, ONO-8590580 may counteract this pathological tonic inhibition.[1] |
Solubility Data
| Solubility (In Vitro) | DMSO : ~62.5 mg/mL (~166.03 mM) |
| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.08 mg/mL (5.53 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.08 mg/mL (5.53 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 2.6565 mL | 13.2827 mL | 26.5654 mL | |
| 5 mM | 0.5313 mL | 2.6565 mL | 5.3131 mL | |
| 10 mM | 0.2657 mL | 1.3283 mL | 2.6565 mL |