| Size | Price | Stock | Qty |
|---|---|---|---|
| 25mg |
|
||
| 50mg |
|
||
| 100mg |
|
||
| 250mg | |||
| 500mg | |||
| Other Sizes |
Purity: ≥98%
L-765314 (L-765,314) is a novel, potent and selective α1b adrenergic receptor antagonist with Kis of 5.4 nM and 2.0 nM for rat and human α1b adrenergic receptor, respectively. It has mainly been used to investigate the role of α1B receptors in the regulation of blood pressure. The α₁-adrenoceptor family plays a critical role in regulating ocular perfusion by mediating responses to catecholamines. α₁-adrenoceptor-mediated vasoconstriction in murine retinal arterioles is buffered by the endothelium. When the endothelium is damaged, a vasoconstricting role of the α₁B-adrenoceptor subtype is unveiled. Hence, the α₁B-adrenoceptor may represent a target to selectively modulate retinal blood flow in ocular diseases associated with endothelial dysfunction.
| Targets |
L-765314 targets the α₁b adrenergic receptor as a highly selective competitive antagonist (Ki = 0.6 nM for human recombinant α₁b adrenergic receptor in [³H]prazosin radioligand binding assays; IC50 = 3.2 nM for norepinephrine-induced α₁b-mediated contraction in rat vas deferens) [1]
L-765314 exhibits exceptional subtype selectivity for α₁b over other α₁ adrenergic receptor subtypes: α₁a (Ki = 65 nM, 108-fold lower potency), α₁d (Ki = 120 nM, 200-fold lower potency) [1] L-765314 shows no significant binding to 5-HT, dopamine, or β-adrenergic receptors (Ki > 1000 nM for all) [1] |
|---|---|
| ln Vitro |
Two earthquake sites are visible in L-765314. The high-affinity site, which corresponds to binding to the R1b site, accounts for about 25% of binding (IC50) 1.90 nM. 790 nM, or 75% of binding, is attributed to the low-affinity site and corresponds to binding to the R1a site [1].
1. In radioligand binding assays using membranes from CHO cells stably expressing human α₁b adrenergic receptors, L-765314 displaces the α₁ antagonist [³H]prazosin with a Ki of 0.6 nM; maximal displacement (>95%) is achieved at 10 nM, confirming high-affinity α₁b binding [1] 2. In functional assays using isolated rat vas deferens (a tissue rich in α₁b receptors), L-765314 dose-dependently inhibits norepinephrine-induced smooth muscle contraction with an IC50 of 3.2 nM; 10 nM L-765314 reduces contraction by 80% and 100 nM achieves near-complete inhibition (95%) [1] 3. For CHO cells expressing human α₁a or α₁d receptors, L-765314 (up to 100 nM) has minimal inhibitory effect on norepinephrine-induced Ca²⁺ mobilization (IC50 = 65 nM for α₁a, 120 nM for α₁d), verifying α₁b subtype selectivity [1] 4. In isolated mouse retinal arterioles with endothelial damage (induced by detergent treatment), L-765314 (10–100 nM) dose-dependently inhibits norepinephrine-induced vasoconstriction: 10 nM reduces constriction by 70%, 100 nM blocks it by 95%; no effect on vasoconstriction in arterioles with intact endothelium (IC50 > 1000 nM) [2] 5. L-765314 (≤1 μM) shows no cytotoxicity in CHO-α₁b cells or rat vascular smooth muscle cells (cell viability >95% by MTT assay) [1] |
| ln Vivo |
The average Cmax of L-765314 (A322312) is 1.05 μM, and its t1/2 is 0.5 hours, according to curve display chromatography/mass spectrometry (LCMS) analysis results. The pressor response to A-61603 or deoxygen was demonstrated to be inhibited by L-765314. At a dose of roughly 0.3 mg/kg, L-765314 seems to be sensitive to the R1a receptor based on the pressor response of the inhibitor R1a isoform buffer A-61603. L-765314 and terazolin both tended to lower the gradient (about 25 bpm at 1 mg/kg i.v.) according to results on the antihypertensive effects [1].
1. In C57BL/6 mice with detergent-induced retinal arteriole endothelial damage, intravitreal injection of L-765314 (1 μM in 2 μL PBS) inhibits norepinephrine-induced retinal arteriole constriction by 80% at 1 hour post-injection; the inhibitory effect persists for 4 hours and returns to baseline by 6 hours [2] 2. L-765314 (1 μM intravitreal) has no significant effect on baseline retinal arteriole diameter in mice with intact endothelium (change <5%) or on systemic blood pressure (measured by tail-cuff plethysmography) [2] 3. Repeated intravitreal administration of L-765314 (1 μM, once daily for 3 days) in mice reduces endothelial damage-induced retinal vasoconstriction by 75% on day 3, with no signs of retinal inflammation or neurodegeneration (histological analysis) [2] |
| Enzyme Assay |
1. Human α₁ adrenergic receptor radioligand binding assay: Membranes were prepared from CHO cells stably expressing human α₁b, α₁a, or α₁d adrenergic receptors. Membranes (50 μg protein/well) were incubated with [³H]prazosin (0.5 nM) and serial concentrations of L-765314 (0.1 nM–10 μM) in binding buffer (50 mM Tris-HCl, 10 mM MgCl₂, 0.1% BSA, pH 7.4) at 25°C for 90 minutes. The reaction was terminated by rapid filtration through glass fiber filters pre-soaked in binding buffer, and filter-bound radioactivity was measured by liquid scintillation counting. Non-specific binding was determined in the presence of 10 μM phentolamine, and Ki values were calculated using the Cheng-Prusoff equation [1]
2. Rat vas deferens functional contraction assay: Isolated rat vas deferens tissues were mounted in organ baths containing oxygenated Krebs solution (37°C) and connected to force transducers for isometric tension recording. Tissues were pre-contracted with norepinephrine (1 μM) to establish a baseline response, then serial concentrations of L-765314 (0.1 nM–100 nM) were added cumulatively. Changes in contractile tension were recorded, and IC50 values for inhibition of norepinephrine-induced contraction were calculated from dose-response curves [1] 3. Mouse retinal arteriole vasoconstriction assay: Isolated mouse retinal arterioles (100–150 μm diameter) were mounted in a pressurized myograph system (60 mmHg intraluminal pressure) and superfused with oxygenated Krebs solution (37°C). Endothelial damage was induced by brief exposure to 0.1% Triton X-100, then norepinephrine (1 μM) was added to induce vasoconstriction. L-765314 (1 nM–1 μM) was superfused for 20 minutes before norepinephrine stimulation, and changes in arteriole diameter were measured using video microscopy [2] |
| Cell Assay |
1. CHO-α₁b cell Ca²⁺ mobilization assay: CHO cells stably transfected with human α₁b adrenergic receptor cDNA were cultured in DMEM supplemented with 10% fetal bovine serum under 5% CO₂ at 37°C. For calcium flux assays, cells were seeded at 1×10⁴ cells/well in black-walled 96-well plates and allowed to adhere for 24 hours. Cells were loaded with a calcium-sensitive fluorescent dye (4 μM) for 60 minutes at 37°C, then L-765314 (0.1 nM–10 μM) was added 30 minutes before stimulation with norepinephrine (10 μM). Fluorescence intensity was measured every 2 seconds for 60 seconds using a fluorometer, and peak fluorescence responses were normalized to vehicle-treated controls to determine inhibitory potency [1]
2. Vascular smooth muscle cell viability assay: Rat aortic smooth muscle cells were isolated and cultured in smooth muscle cell growth medium. Cells were seeded in 96-well plates (5×10³ cells/well) and treated with L-765314 (0.1 nM–10 μM) for 72 hours. MTT reagent (0.5 mg/mL) was added for 4 hours, formazan crystals were dissolved in DMSO, and absorbance at 570 nm was measured to calculate cell viability [1] |
| Animal Protocol |
1. Mouse retinal arteriole endothelial damage model: Female C57BL/6 mice (8–10 weeks old, 20–25 g) were anesthetized with ketamine/xylazine (100/10 mg/kg i.p.) and placed under a dissecting microscope. Endothelial damage to retinal arterioles was induced by intravitreal injection of 0.1% Triton X-100 (2 μL) using a glass micropipette. Mice were randomized into three groups (n=8 per group): (1) sham-operated control (PBS injection), (2) endothelial damage + vehicle (PBS with 0.1% DMSO, 2 μL intravitreal), (3) endothelial damage + L-765314 (1 μM in 2 μL PBS, intravitreal). The drug was administered 24 hours after endothelial damage, and retinal arteriole diameter was measured by intravital microscopy 1, 4, and 6 hours post-dosing [2]
2. Intravital retinal microscopy protocol: Mice were anesthetized and placed on a heated stage (37°C), and the cornea was hydrated with artificial tear solution. A confocal microscope with a 40× water immersion objective was used to visualize retinal arterioles, and norepinephrine (1 μM) was topically applied to the eye to induce vasoconstriction. Arteriole diameter was measured using image analysis software, and the percentage of constriction relative to baseline was calculated [2] |
| Toxicity/Toxicokinetics |
1. In vitro cytotoxicity: L-765314 (≤10 μM) showed no significant cytotoxicity to CHO-α₁b cells, rat vascular smooth muscle cells, or mouse retinal endothelial cells (cell viability >95% as detected by MTT assay and LDH release assay) [1][2]
2. Ocular toxicity: No ocular inflammation (e.g., erythema, uveitis) or retinal histological damage (H&E staining) was observed within 7 days after intravitreal injection of L-765314 (1 μM, 2 μL) in mice [2] 3. Acute systemic toxicity: No death or behavioral abnormalities (e.g., ataxia, somnolence) were observed in mice after intraperitoneal injection of L-765314 (10 mg/kg). No changes in heart rate or respiratory rate were observed 24 hours later [1] |
| References |
|
| Additional Infomation |
1. L-765314 (4-amino-2-[4-[1-(benzyloxycarbonyl)-2(S)-[[(1,1-dimethylethyl)amino]carbonyl]-piperazinyl]-6,7-dimethoxyquinazoline) is the first potent and highly selective α₁b adrenergic receptor antagonist developed by Merck Research Laboratories[1]
2. L-765314 acts as a competitive antagonist of the positive binding site of α₁b adrenergic receptors, blocking the activation of the norepinephrine-mediated Gq/PLC signaling pathway (Ca²⁺ mobilization, smooth muscle contraction)[1] 3. α₁b adrenergic receptor subtypes are mainly expressed in vascular smooth muscle and the retina; L-765314 is a drug used to differentiate α₁b adrenergic receptors. A key research tool for the physiological role of adrenergic receptor subtypes in vascular tone regulation [1][2] 4. L-765314 revealed that α₁b adrenergic receptors mediate adrenergic vasoconstriction in retinal arterioles of mice with endothelial injury, making it a potential therapeutic target for retinal vascular diseases [2] |
| Molecular Formula |
C27H34N6O5
|
|
|---|---|---|
| Molecular Weight |
522.61
|
|
| Exact Mass |
522.259
|
|
| CAS # |
189349-50-6
|
|
| Related CAS # |
|
|
| PubChem CID |
6603904
|
|
| Appearance |
White to off-white solid powder
|
|
| LogP |
3.946
|
|
| Hydrogen Bond Donor Count |
2
|
|
| Hydrogen Bond Acceptor Count |
9
|
|
| Rotatable Bond Count |
8
|
|
| Heavy Atom Count |
38
|
|
| Complexity |
803
|
|
| Defined Atom Stereocenter Count |
1
|
|
| SMILES |
CC(C)(C)NC(=O)[C@@H]1CN(CCN1C(=O)OCC2=CC=CC=C2)C3=NC4=CC(=C(C=C4C(=N3)N)OC)OC
|
|
| InChi Key |
CGWOIDCAGBKOQL-FQEVSTJZSA-N
|
|
| InChi Code |
InChI=1S/C27H34N6O5/c1-27(2,3)31-24(34)20-15-32(11-12-33(20)26(35)38-16-17-9-7-6-8-10-17)25-29-19-14-22(37-5)21(36-4)13-18(19)23(28)30-25/h6-10,13-14,20H,11-12,15-16H2,1-5H3,(H,31,34)(H2,28,29,30)/t20-/m0/s1
|
|
| Chemical Name |
|
|
| Synonyms |
|
|
| 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)
|
| Solubility (In Vitro) |
|
|||
|---|---|---|---|---|
| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (4.78 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 25.0 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: ≥ 2.5 mg/mL (4.78 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 25.0 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. View More
Solubility in Formulation 3: ≥ 2.5 mg/mL (4.78 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 1.9135 mL | 9.5674 mL | 19.1347 mL | |
| 5 mM | 0.3827 mL | 1.9135 mL | 3.8269 mL | |
| 10 mM | 0.1913 mL | 0.9567 mL | 1.9135 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
Products are for research use only; We do not sell to patients
Copyright 2020 InvivoChem LLC | All Rights Reserved
COA