Via A2AR, inosine dose-dependently increases the synthesis of cAMP [2]. Inosine dose-dependently increases hA2AR-mediated ERK1/2 phosphorylation [2]. Inosine (100 μM; 24 hours) decreases oxidative stress in MES 23.5 cells grown with astrocytes [3].

Animal/Disease Models: Male/female C57BL/6 mice [2]
Doses: 1 mg/kg, 10 mg/kg, 100 mg/kg
Route of Administration: intraperitoneal (ip) injection, 20 minutes before formalin. Treatment
Experimental Results: Formalin (2%; 20 μL; plantar injection)-induced withdrawal behavior was diminished.

Absorption, Distribution and Excretion
Ingested inosine is absorbed from the small intestine.

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Metabolism / Metabolites
In the liver, inosine may be catabolized by a series of reactions culminating in the production of uric acid and also may be metabolized to adenine- and guanine-containing nucleotides. Inosine not metabolized in the liver is transported via the systemic circulation and distributed to various tissues of the body, where it is metabolized in similar fashion as in the liver. Uric acid, the purine end-product of inosine catabolism, is excreted in the urine.

[1]. Filipe Marques Gonçalves, et al. Signaling pathways underlying the antidepressant-like effect of inosine in mice. Purinergic Signal. 2017 Jun; 13(2): 203-214.
[2]. Francisney Pinto Nascimento, et al. Adenosine A1 receptor-dependent antinociception induced by inosine in mice: pharmacological, genetic and biochemical aspects. Mol Neurobiol. 2015;51(3):1368-78.
[3]. Ajith A. Welihinda, et al. The adenosine metabolite inosine is a functional agonist of the adenosine A2A receptor with a unique signaling bias. Cell Signal. 2016 Jun; 28(6): 552-560.
[4]. Sara Cipriani, et al. Protection by inosine in a cellular model of Parkinson’s disease. Neuroscience. 2014 Aug 22; 274: 242-249.

Inosine is a purine nucleoside in which hypoxanthine is attached to ribofuranose via a beta-N(9)-glycosidic bond. It has a role as a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and a mouse metabolite. It is a purines D-ribonucleoside and a member of inosines. It is functionally related to a hypoxanthine and a ribofuranose.
A purine nucleoside that has hypoxanthine linked by the N9 nitrogen to the C1 carbon of ribose. It is an intermediate in the degradation of purines and purine nucleosides to uric acid and in pathways of purine salvage. It also occurs in the anticodon of certain transfer RNA molecules. (Dorland, 28th ed)
Inosine is a metabolite found in or produced by Escherichia coli (strain K12, MG1655).
Inosine has been reported in Daphnia pulex, Fritillaria thunbergii, and other organisms with data available.
Inosine is a metabolite found in or produced by Saccharomyces cerevisiae.
A purine nucleoside that has hypoxanthine linked by the N9 nitrogen to the C1 carbon of ribose. It is an intermediate in the degradation of purines and purine nucleosides to uric acid and in pathways of purine salvage. It also occurs in the anticodon of certain transfer RNA molecules. (Dorland, 28th ed)

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Drug Indication
The primary popular claim made for inosine, that it enhances exercise and athletic performance, is refuted by the available research data. There is some preliminary evidence that inosine may have some neurorestorative, anti-inflammatory, immunomodulatory and cardioprotective effects.

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Mechanism of Action
Inosine has been found to have potent axon-promoting effects in vivo following unilateral transection of the corticospinal tract of rats. The mechanism of this action is unclear. Possibilities include serving as an agonist of a nerve growth factor-activated protein kinase (N-Kinase), conversion to cyclic nucleotides that enable advancing nerve endings to overcome the inhibitory effects of myelin, stimulation of differentiation in rat sympathetic neurons, augmentation of nerve growth factor-induced neuritogenesis and promotion of the survival of astrocytes, among others. The mechanism of inosine's possible cardioprotective effect is similarly unclear. Inosine has been reported to have a positive inotropic effect and also to have mild coronary vasodilation activity. Exogenous inosine may contribute to the high-energy phosphate pool of cardiac muscle cells and favorably affect bioenergetics generally. Inosine has also been reported to enhance the myocardial uptake of carbohydrates relative to free fatty acids as well as glycolysis. In cell culture studies, inosine has been found to inhibit the production, in immunostimulated macrophages and spleen cells, of the proinflammatory cytokines, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, interleukin (IL)-12, macrophage-inflammatory protein-1 alpha and interferon (IFN)-gamma. It also suppressed proinflammatory cytokine production and mortality in a mouse endotoxemic model. These actions might account for the possible immunomodulatory, anti-inflammatory and anti-ischemic actions of inosine.

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Pharmacodynamics
Inosine may have neuroprotective, cardioprotective, anti-inflammatory and immunomodulatory activities.

C10H12N4O5

268.23

268.08

58-63-9

Inosine-13C5;Inosine-2,8-d2;697807-01-5;Inosine-13C

135398641

Typically exists as solid at room temperature

2.1±0.1 g/cm3

670.5±65.0 °C at 760 mmHg

222-226 °C (dec.)(lit.)

359.3±34.3 °C

0.0±2.2 mmHg at 25°C

1.879

-1.91

4

7

2

19

405

4

O1[C@]([H])(C([H])([H])O[H])[C@]([H])([C@]([H])([C@]1([H])N1C([H])=NC2C(N([H])C([H])=NC1=2)=O)O[H])O[H]

UGQMRVRMYYASKQ-KQYNXXCUSA-N

InChI=1S/C10H12N4O5/c15-1-4-6(16)7(17)10(19-4)14-3-13-5-8(14)11-2-12-9(5)18/h2-4,6-7,10,15-17H,1H2,(H,11,12,18)/t4-,6-,7-,10-/m1/s1

9-[(2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]-1H-purin-6-one

NSC-20262; NSC 20262; Inosine

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)

DMSO : ~100 mg/mL (~372.81 mM)
H2O : ~10 mg/mL (~37.28 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (9.32 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.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (9.32 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.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (9.32 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 corn oil and mix evenly.

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Solubility in Formulation 4: 15.56 mg/mL (58.01 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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