Dopamine D4 receptor (D4R) – partial agonist [1]
Ro 10-5824 targets the dopamine D4 receptor (D4R), a G protein-coupled receptor of the D2-like family. As a selective partial agonist, it binds to the D4 receptor with high affinity (Ki = 5.2 nM) and activates it to a lesser extent than a full agonist. The compound exhibits minimal activity at other dopamine receptor subtypes such as D2 and D3. Its selectivity for D4 over other dopamine receptors makes it a valuable tool for studying D4 receptor function and its role in neurological and psychiatric disorders.

In vitro, Ro 10-5824 demonstrates potent and selective D4 receptor agonism. In radioligand binding assays, it shows high affinity for the human D4 receptor with a Ki of 5.2 nM. It displays 250-fold selectivity over D3 receptors and greater than 1000-fold selectivity over D2, D1, and D5 receptors. In functional assays, it acts as a partial agonist, activating the receptor to a lesser extent than full agonists. Its unique pharmacological profile makes it a valuable tool for studying D4 receptor function.

Rationale: Growing evidence suggests that dopamine D4 receptors (D4Rs) are involved in controlling executive functions. We have previously demonstrated that Ro 10-5824, a D4R partial agonist, improves the performance of common marmosets in the object retrieval detour (ORD) task. However, the neural mechanisms underlying this improvement are unknown.
Objectives: We investigated the behavioral and neurophysiological effects of Ro 10-5824 in common marmosets.
Methods: The effects of Ro 10-5824 on cognitive function were evaluated using the ORD task. The neurophysiological effects of Ro 10-5824 were investigated by quantitative electroencephalography, especially on baseline gamma band activity in the frontal cortex. The effects of Ro 10-5824 on spontaneous locomotion were also assessed.
Results: Systemic administration of Ro 10-5824 at 3 mg/kg significantly increased the success rate in the ORD task. At doses of 1 and 3 mg/kg, Ro 10-5824 increased baseline gamma band activity in the frontal cortex. Ro 10-5824 had no effect on spontaneous locomotion.
Conclusions: Activation of D4R by Ro 10-5824 improves the success rate in the ORD task and increases baseline gamma band activity in the frontal cortex without affecting locomotion in common marmosets. These findings highlight the role of D4R in gamma oscillations of non-human primates. As gamma oscillations are thought to be involved in attention and behavioral inhibition, our results suggest D4R agonists may improve these cognitive functions by modulating baseline gamma band activity in the frontal cortex.
Ro 10-5824 (CAS#: 189744-46-5) in vivo in common marmosets:
1) ORD task: Intramuscular administration at 3 mg/kg significantly increased the success rate in the difficult trial (p = 0.0024), but had no effect on the easy trial (p = 0.5136). Doses of 0.3 and 1 mg/kg showed no statistically significant improvement in the difficult trial. [1]
2) Quantitative EEG: At doses of 1 and 3 mg/kg, Ro 10-5824 significantly increased gamma band (30-80 Hz) power in the frontal cortex (p < 0.01) and decreased alpha band (8-12 Hz) power (p < 0.05), with no significant effect on beta band (12-30 Hz). The increase in gamma power was dose- and time-dependent; at 3 mg/kg the effect persisted for up to 80 min, while at 1 mg/kg it faded around 40 min post-injection. [1]
3) Locomotor activity: Ro 10-5824 at 1 and 3 mg/kg had no significant effect on spontaneous locomotion in common marmosets (no significant time by treatment interaction). [1]
In vivo, Ro 10-5824 has been studied for its potential therapeutic applications. It has been investigated for the treatment of cocaine use disorders, as dopaminergic mechanisms play a prominent role in cocaine abuse-related effects. The compound also has potential implications in treating psychiatric conditions such as Attention Deficit Hyperactivity Disorder (ADHD) and schizophrenia. It stimulates motor activity in rats without influencing reward-related behavior. However, specific in vivo efficacy data are limited in the available literature.

In vitro receptor binding assays for Ro 10-5824 use membrane preparations from cells expressing recombinant human dopamine D4 receptors. Radioligand binding studies employ [³H]-spiperone or other suitable tracers. Membranes are incubated with varying concentrations of Ro 10-5824 in binding buffer (e.g., 50 mM Tris-HCl, pH 7.4, 120 mM NaCl, 5 mM KCl, 2 mM CaCl₂, 1 mM MgCl₂) at room temperature for 60-90 minutes. Bound and free ligands are separated by filtration through GF/B filters, and radioactivity is counted. IC₅₀ or Kᵢ values are calculated from competition binding curves. For functional assays, calcium mobilization or GTPγS binding assays are used to measure receptor activation.

In vitro cell-based assays for Ro 10-5824 use cell lines expressing recombinant human dopamine D4 receptors (e.g., CHO or HEK293 cells). Cells are cultured in appropriate media (e.g., DMEM/F12 with 10% FBS, 37°C, 5% CO₂) and treated with Ro 10-5824 at various concentrations (0.01 nM to 10 μM). Receptor activation is assessed by measuring intracellular calcium levels using fluorescent indicators (Fura-2 or Fluo-4) or by measuring cAMP accumulation. GTPγS binding assays can also be used to measure receptor activation. Cell viability is assessed by MTT assays.

Animal protocols (from [1]):
ORD task: Common marmosets (n=6, 3 males, 3 females, 3 years old) were trained to reach a reward in a transparent acrylic box. A session consisted of 9 easy trials (reward placed at open side) and 8 difficult trials (reward opposite open side, requiring detour). Saline or Ro 10-5824 (0.3, 1, 3 mg/kg) was injected intramuscularly into the femoral muscle at 0.5 mL/kg, 60 min before task. Difference in success rate was calculated as (N_drug-treated − N_drug-free) × 100 / 8 or 9. Experiments were separated by at least 1 week, pseudo-randomized crossover. Data analyzed by non-parametric Friedman's test followed by post hoc Bonferroni-Dunn test. [1]
EEG recording: Five marmosets (4 males, 1 female, 2.5-5 years old) had skull-implanted electrodes (bilateral frontal cortices: AP +12.5 mm, Lat ±3.0 mm relative to bregma). After ≥10 days recovery, EEG was recorded wirelessly (sampling rate 512 Hz) in a sound-proof box. After 30 min baseline, saline or Ro 10-5824 (1, 3 mg/kg, i.m., 0.5 mL/kg) was injected, followed by 80 min post-drug recording. Data from both frontal cortices averaged. Spectral power calculated by FFT in consecutive 4-s epochs (0.75 Hz high-pass filter). Epochs with amplitude >1000 μV excluded. Power in alpha (8-12 Hz), beta (12-30 Hz), gamma (30-80 Hz) bands normalized to baseline. Statistics: two-way repeated measures ANOVA followed by post hoc Dunnett test. [1]
Locomotor activity: Five marmosets (3 males, 2 females, 2-3 years old) were tested in home cages using infrared passive sensors (SUPERMEX). After 30 min baseline, saline or Ro 10-5824 (1, 3 mg/kg, i.m., 0.5 mL/kg) was injected, followed by 120 min recording. Counts summed every 10 min, normalized to baseline. Two-way repeated measures ANOVA with Dunnett test. [1]
In vivo animal studies for Ro 10-5824 have been conducted in rat models to study its effects on motor activity and reward-related behavior. The compound is typically administered via intraperitoneal or subcutaneous injection at doses ranging from 0.1 to 10 mg/kg. Behavioral assays, such as locomotor activity tests, are performed to assess the compound's effects on motor function. Conditioned place preference or self-administration paradigms may be used to study reward-related behavior. Pharmacokinetic studies involve collecting blood and brain tissue samples for drug concentration analysis.

Specific pharmacokinetic properties of Ro 10-5824, such as half-life and oral bioavailability, are not extensively detailed in the available literature. As a small molecule with a molecular weight of 310.39 g/mol, it is likely to have good oral bioavailability and brain penetration. It is soluble in DMSO and is typically administered via injection in research settings. The compound's pharmacokinetic profile supports its use as a research tool for studying D4 receptor function.

Comprehensive toxicological data for Ro 10-5824 are not provided in the available literature. As a research compound, it is intended for laboratory use only and is not for human therapeutic use. Standard safety precautions should be followed when handling this compound. The dihydrochloride salt form is available with high purity (≥98%). Ro 10-5824 is not approved for clinical use.

Psychopharmacology (Berl). 2015 Sep;232(17):3287-95.;Neuropharmacology. 2003 Mar;44(4):473-81.

2-Methyl-5-[(4-phenyl-3,6-dihydro-2H-pyridin-1-yl)methyl]-4-pyrimidineamine is an aminopyrimidine.

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Ro 10-5824 (CAS#: 189744-46-5) is a dopamine D4 receptor partial agonist (previously characterized by Powell et al., 2003). In this study, it showed no motor impairment or effect on spontaneous locomotion, indicating the cognitive improvement in the ORD task is not due to motor effects. The increase in baseline gamma band activity and decrease in alpha band activity in the frontal cortex suggest D4R activation modulates neural oscillations, which may underlie improvements in attention and behavioral inhibition. The study highlights D4R as a potential target for disorders such as ADHD, where abnormal gamma oscillations have been reported. No clinical development or FDA information is provided. [1]
Ro 10-5824 is a selective partial agonist of the dopamine D4 receptor developed by Hoffmann-La Roche. It exhibits high binding affinity (Ki = 5.2 nM) and exceptional selectivity over other dopamine receptor subtypes. The compound has been investigated for potential therapeutic applications in cocaine use disorders, ADHD, and schizophrenia. Its unique pharmacological profile makes it a valuable tool for studying D4 receptor function and its role in neurological and psychiatric disorders. This product is for research use only.

C17H20N4.2[HCL]

353.28938

352.122

C, 72.83; H, 7.19; N, 19.98

189744-46-5

189744-46-5; 189744-94-3 (2HCl-dihydrochloride salt)

16759175

Solid powder

506.2ºC at 760 mmHg

260ºC

1.28E-10mmHg at 25°C

4.779

1

4

3

21

362

0

Cl.Cl.C1(C2=CCN(CC3=CN=C(C)N=C3N)CC2)C=CC=CC=1

KABDATZAOUSYES-UHFFFAOYSA-N

InChI=1S/C17H20N4/c1-13-19-11-16(17(18)20-13)12-21-9-7-15(8-10-21)14-5-3-2-4-6-14/h2-7,11H,8-10,12H2,1H3,(H2,18,19,20)

2-methyl-5-((4-phenyl-5,6-dihydropyridin-1(2H)-yl)methyl)pyrimidin-4-amine

RO10-5824; RO 10-5824; RO-10-5824; RO105824; RO 105824; RO-105824.

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)