Dopamine receptor

Aromatic L-amino acid decarboxylase (EC. 4.1.1.28) deficiency is a newly described inborn error of metabolism that affects serotonin and dopamine biosynthesis. The major biochemical markers for this disease are increases of L-dopa, 3-methoxytyrosine, and 5-hydroxytryptophan in urine, plasma, and cerebrospinal fluid together with decreased cerebrospinal fluid concentrations of homovanillic acid and 5-hydroxyindoleacetic acid. In addition, concentrations of vanillactic acid are increased in the urine. Specific HPLC and gas chromatography-mass spectrometry methods are described that permit the identification and measurement of these metabolites in the above body fluids. Simplified assays for human plasma L-dopa decarboxylase and liver L-dopa and 5-hydroxytryptophan decarboxylase, used to demonstrate the enzyme deficiency, are also reported[1].

Oral L-DOPA sodium (20 mg/kg) lessens motor impairment brought on by rotenone [3]. In sprague-Dawley rats, oral administration of L-DOPA sodium (0–100 mg/kg) reverses tactile, heat, and cold allodynia without causing any adverse consequences [4].

Animal/Disease Models: C57BL/6J mice (7 weeks old) [3]
Doses: 20 mg/kg
Route of Administration: Oral
Experimental Results: diminished rotenone-induced motor dysfunction.

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Animal/Disease Models: SD (SD (Sprague-Dawley)) rat [4]
Doses: 10, 30, 50, 70 and 100 mg/kg
Route of Administration: Orally
Experimental Results:Reverse tactile, hot and cold allodynia in neuropathic rats without any side effects.

[1]. Aromatic L-amino acid decarboxylase deficiency: diagnostic methodology. Clin Chem. 1992 Dec;38(12):2405-10.

[2]. Dopamine dysregulation syndrome, addiction and behavioral changes in Parkinson's disease. Parkinsonism Relat Disord. 2008;14(4):273-80. Epub 2007 Nov 7.

[3]. Additive Effects of Levodopa and a Neurorestorative Diet in a Mouse Model of Parkinson's Disease. Front Aging Neurosci. 2018 Aug 3;10:237.

[4]. Anti-allodynic effects of levodopa in neuropathic rats. Yonsei Med J. 2013 Mar 1;54(2):330-5.

[5]. Pharmacological validation of a mouse model of l-DOPA-induced dyskinesia. Exp Neurol. 2005 Jul;194(1):66-75.

[6]. Pharmacokinetics of L-dopa in plasma and extracellular fluid of striatum in common marmosets. Brain Res. 2003 Dec 12;993(1-2):54-8.

The degeneration of the dopaminergic system in Parkinson's disease and long-term use of dopaminergic drugs may lead to dysfunction of the reward system. This may manifest as addiction to levodopa and behavioral disorders associated with the impulse control system. These disorders include gambling, excessive spending (shopping), hypersexuality, and binge eating. We have included a patient’s personal account to highlight the devastating consequences of these potentially reversible phenomena: the patient described in his own words how gambling behavior induced by exposure to dopamine agonist treatment significantly exacerbated his disease-related problems. [2]

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Although the clinical presentation of Parkinson's disease (PD) is usually dominated by motor disorders, non-motor symptoms such as cognitive decline and gastrointestinal dysfunction may precede motor symptoms and have a significant impact on quality of life. Levodopa (L-3,4-dihydroxyphenylalanine) is the most commonly used drug for treating motor symptoms, but long-term use can produce serious side effects and cannot stop the progression of degenerative changes. In addition, gastrointestinal dysfunction can interfere with the absorption of levodopa and affect its efficacy. Since most patients are receiving levodopa, combination therapy is needed to effectively alleviate motor and nonmotor symptoms. Our recent study has shown that a diet containing precursors and cofactors required for membrane phospholipid synthesis, as well as prebiotic fiber, has a therapeutic effect in a mouse model of Parkinson's disease. Now, we investigated the effects of combining the above diet with levodopa in a rotenone-induced Parkinson's disease model. Rotenone or its carrier was injected into the striatum of mice. Dietary intervention was initiated after complete induction of motor symptoms. The effects of dietary intervention and different doses of oral levodopa were assessed weekly. Motor and cognitive functions were tested, intestinal transit was analyzed, and the histology of the brain and colon was evaluated. Our results confirm our previous findings that an active diet (AD) can alleviate rotenone-induced motor and nonmotor problems. In rotenone-treated animals fed AD, levodopa had an additional beneficial effect on rotarod test performance. No negative interaction between AD and levodopa was found. Our results suggest that dietary intervention may provide additional clinical benefits to patients receiving levodopa. [3]

220.05857

63302-01-2

L-DOPA;59-92-7

138683040

Typically exists as solid at room temperature

4

5

3

15

209

1

BDARLFNIXLYGPC-RGMNGODLSA-N

InChI=1S/C9H11NO4.Na/c10-6(9(13)14)3-5-1-2-7(11)8(12)4-5;/h1-2,4,6,11-12H,3,10H2,(H,13,14);/t6-;/m0./s1

Levodopa sodium; Levodopa (sodium);3,4-Dihydroxyphenylalanine (sodium); SCHEMBL21055745; AKOS040752531

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.)