IngredientsPrimary chemical name: 3,7-Dimethyl-1-(2-propynyl)xanthine. The compound is universally abbreviated as DMPX. Its empirical formula is C10H10N4O2, its CAS number is 14114-46-6, and its molecular weight is 218.21 g/mol.
DMPX is a caffeine analog and A2-selective adenosine receptor (AR) antagonist. The compound belongs to the xanthine alkaloid class — the same chemical family as caffeine (1,3,7-trimethylxanthine), theophylline (1,3-dimethylxanthine), and theobromine (3,7-dimethylxanthine). DMPX was the first A2-adenosine receptor-selective antagonist described in the literature, introduced by Ukena et al. (1986) and later further characterized by Seale et al. (1988).
Unlike its parent compounds caffeine and theophylline, DMPX is not a naturally occurring substance. The first "selective" A2A adenosine receptor antagonist described in the literature was the caffeine analogue DMPX, which, like caffeine, possesses low A2A AR affinity and moderate selectivity compared with A1 ARs; nevertheless, the compound has been widely used in in vivo studies because of its good water solubility and bioavailability.
Physical form and availability. DMPX is commercially available as a powder of ≥98% purity by HPLC. It is catalogued in Sigma-Aldrich's Library of Pharmacologically Active Compounds (LOPAC 1280), a biologically annotated reference collection used in research screening. All commercial sources label it for research use only and explicitly not for human or veterinary use.
DMPX itself has no known natural botanical or dietary source. It is a fully synthetic molecule constructed in the laboratory. However, it is structurally related to the naturally occurring methylxanthines found in food plants. Xanthine derivatives such as caffeine and theobromine, found naturally in coffee and tea, have been used for centuries to promote alertness, increase stamina, and support overall well-being. 1,3,N-Dipropyl-7-Propargylxanthine is a synthetic derivative of xanthine, a class of compounds that have long been associated with medicinal and therapeutic benefits.
The xanthine scaffold itself is a naturally occurring purine base found in nearly all tissues of the body and in many food plants, where it serves as an intermediate in the catabolism of purines. DMPX was designed by medicinal chemists to exploit and sharpen the adenosine receptor pharmacology of this natural scaffold, specifically by incorporating a propargyl (prop-2-yn-1-yl) group at the N-1 position of the xanthine ring — a modification that confers preference for the A2A adenosine receptor subtype over the A1 subtype.
Because DMPX is a fully synthetic compound first described in 1986, it has no traditional or historical use in any medical, herbal, or nutritional tradition. Its pharmacological history begins entirely within the modern scientific literature.
The broader xanthine class to which DMPX belongs does carry a long history of human use. Historically, xanthine-based compounds have been used as remedies for respiratory issues, fatigue, and headaches. Theophylline, a close structural relative, has been in medical use as a bronchodilator since the early 20th century, and caffeine-containing plants such as Coffea arabica, Camellia sinensis (tea), and Theobroma cacao (cocoa) have been consumed across multiple world cultures for several centuries. DMPX was developed by pharmaceutical chemists building on this xanthine tradition to create a tool compound with improved A2A receptor selectivity. Building on this rich tradition, DMPX was developed to harness and enhance the beneficial properties of xanthines, particularly in research aimed at mental clarity and energy.
DMPX is a pure, single-component synthetic compound. Its structure is characterized by:
Certain alkyl modifications at the 1-, 3-, and 7-positions — as exemplified by DMPX — favor A2 affinity to some extent, though the degree of selectivity versus A1 receptors is comparatively modest in the parent compound. DMPX is similarly potent at A2A and A2B adenosine receptors, but the degree of selectivity versus A1 ARs is low; a comparison with the 7-unmethylated derivative 3-methyl-1-propargylxanthine indicated that a 7-methyl group led to a large decrease in A1 AR affinity and thus increased selectivity for A2A or A2B AR.
DMPX is a selective A2A adenosine receptor (A2A AR) antagonist that crosses the blood-brain barrier, with a Ki of 11 μM for the rat A2 adenosine receptor and a Ki of 45 μM for the rat A1 adenosine receptor. This approximately four-fold difference in binding affinity between A2A and A1 receptors reflects DMPX's relative — though modest — selectivity for A2A over A1 subtypes.
3,7-Dimethyl-1-propargylxanthine (DMPX) exhibits a somewhat higher affinity for the A2A versus the A1 receptor, and has thus been used in vitro and in vivo as the first "A2A-selective" AR antagonist; however, DMPX is only very moderately selective with respect to A1 and it is not selective versus the A2B receptor.
DMPX, a caffeine analog that exhibits in vitro selectivity for A2-adenosine receptors compared to A1-adenosine receptors, has been investigated with respect to in vivo potency and selectivity. In in vivo experiments in DBA/2 mice, DMPX potently and selectively blocked the actions of the potent A2 adenosine agonist NECA (5′-N-ethylcarboxamidoadenosine), compared to blockade of the same responses elicited by the selective A1 agonist N6-cyclohexyladenosine (CHA). DMPX was 57-fold more potent versus NECA-induced hypothermia than versus CHA-induced hypothermia, and 11-fold more potent versus NECA-induced behavioral depression than versus CHA-induced behavioral depression.
When compared directly to caffeine, DMPX was 28- and 15-fold more potent than caffeine in blocking peripheral and central NECA-responses, respectively; DMPX was equipotent with caffeine versus CHA-induced hypothermia and 2.5-fold more potent than caffeine versus CHA-induced behavioral depression; the motor stimulating potency of DMPX (ED50 10 μmol/kg) was slightly greater than caffeine.
By blocking A2A receptors in specific brain regions, DMPX protects dopaminergic and GABAergic neurons from mitochondrial dysfunction. This mechanism is central to the neuropharmacological interest in DMPX and explains its relevance to movement disorder research.
Adenosine modulates neuronal function via controlling the release of various neurotransmitters; it highly inhibits dopamine (DA), γ-aminobutyric acid (GABA), glutamate (Glu), acetylcholine (ACh), serotonin (5-HT), and noradrenaline (NA) release. By blocking adenosine A2A receptors, DMPX removes this inhibitory brake, thereby disinhibiting release of multiple neurotransmitters relevant to mood, cognition, and motor control.
A2AR antagonists, through direct and/or indirect modulation of the hypothalamic–pituitary–adrenal (HPA) axis, can influence stress-induced diseases; the effects on the HPA axis may be another underpinning of the behavioral effects following co-administration of DMPX and antidepressants.
Among the adenosine receptor antagonists tested, DMPX was capable of downregulating ABCG2 protein levels in cancer cell lines. ABCG2 is a multidrug resistance efflux transporter, and its downregulation may theoretically enhance intracellular drug retention. This observation is at an early, preclinical stage.
Unsatisfactory therapeutic effects of currently used antidepressants have forced researchers to search for new pharmacological treatment strategies; recent research points to the relationship between depressive disorders and the adenosinergic system.
The most thoroughly characterized preclinical work involves DMPX as an adjunct to standard antidepressants. In a mouse study published in Neurotoxicity Research (PMC6331646), the main goal was to evaluate the effects of DMPX (3 mg/kg, i.p.), which possesses selectivity for adenosine A2A receptors versus A1 receptors, on the activity of imipramine (15 mg/kg, i.p.), escitalopram (2.5 mg/kg, i.p.), and reboxetine (2 mg/kg, i.p.) given in subtherapeutic doses. Studies carried out using the forced swim and tail suspension tests in mice showed that DMPX at a dose of 6 and 12 mg/kg exerts antidepressant-like effect and does not affect the locomotor activity; co-administration of DMPX at a dose of 3 mg/kg with the studied antidepressant drugs caused the reduction of immobility time in both behavioral tests, and the observed effect was not associated with an increase in the locomotor activity.
A subsequent mouse study published in Pharmacological Reports (2019) extended these findings to novel antidepressants. The forced swim test (FST) and tail suspension test (TST) were performed to assess the effects of DMPX on the antidepressant-like activity of agomelatine and tianeptine; drug serum and brain levels were analyzed using HPLC. Co-administration of agomelatine (20 mg/kg) or tianeptine (15 mg/kg) with DMPX (3 mg/kg) significantly reduced the immobility time both in the FST and TST in mice. The observed changes in mouse behavior after co-injection of DMPX and the tested antidepressant agents were associated with elevated brain concentrations of agomelatine and tianeptine; the study concluded a synergistic action of the selective A2A receptor antagonist and the studied antidepressant drugs, a combination that may represent a new strategy for treating depression.
Evidence strength: All antidepressant evidence is preclinical (animal behavioral models). No human clinical trials on DMPX for depression have been published. Results are promising at the mechanistic level but cannot be extrapolated to humans without clinical investigation.
Adenosine A2A receptors are highly concentrated in the striatum, co-localized with dopamine D2 receptors on striatopallidal neurons — a circuit critically affected in Parkinson's disease (PD). A2A receptor antagonists including DMPX, KF 17837, and KW 6002 antagonized catalepsy induced by haloperidol or reserpine in the rat, whereas in non-human primate models of PD, KW 6002 reduced rigidity and improved the disability score of MPTP-treated marmosets and cynomolgus monkeys.
In contrast to L-DOPA, selective A2A receptor antagonists administered chronically did not produce dyskinesias and did not evoke tolerance in 6-OHDA and MPTP models of PD; additional therapeutic potential of adenosine A2A antagonists emerged from studies showing neuroprotective properties of these compounds in animal models of cerebral ischemia and excitotoxicity, as well as in the MPTP model of PD.
In pharmacological MRI (phMRI) brain imaging studies, phMRI with an A2A antagonist DMPX challenge induced regional cerebral blood volume decrease in the caudate–putamen and nucleus accumbens, areas with a dense population of A2A receptors, similar to the regional CBV changes induced by a D2 agonist. This imaging approach has been used to investigate how A2A antagonism interacts with dopaminergic function at the circuit level.
Evidence strength: Evidence for DMPX specifically in PD models is preclinical and largely derived from rodent and non-human primate experiments. DMPX served primarily as a pharmacological probe to establish the feasibility of A2A antagonism in PD; more potent and selective A2A antagonists (e.g., istradefylline/KW-6002) have advanced to clinical trials and regulatory approval, while DMPX itself has not entered human clinical testing for PD.
Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by a mutation in the IT15 gene encoding the huntingtin protein; mutated huntingtin predominantly affects striato-pallidal neurons, which are particularly enriched with adenosine A2A receptors, suggesting a possible involvement of adenosine and A2AR in the pathogenesis of HD.
The influence of DMPX, an adenosine A2 receptor antagonist, was studied in the quinolinic acid (QA) model of Huntington's disease. Administering various A2AR antagonists (including DMPX, SCH58261, ZM241385, ST1535, MSX-3, and CSC) can have multiple beneficial effects; A2AR antagonism can reduce striatal degeneration (atrophy), normalize EEG patterns, and normalize motor activity.
The evidence is complicated by the observation that the role of A2AR in HD may be context-dependent. A2AR antagonism had a potentially detrimental effect on neurotoxicity induced by quinolinic acid in an animal model of HD, specifically there was increased striatal glutamate outflow. This suggests that the net effect of A2AR blockade may differ depending on the HD model system and disease stage studied.
Evidence strength: Exclusively preclinical (rodent and transgenic mouse models). No human clinical trials using DMPX in HD. The overall A2AR antagonism strategy in HD remains an area of active investigation, with complex and sometimes contradictory results across different animal models.
DMPX has been consistently documented to produce locomotor stimulation via central A2A antagonism. The motor stimulating potency of DMPX (ED50 10 μmol/kg) was slightly greater than caffeine. This effect has been used as a pharmacological read-out in in vivo selectivity studies. DMPX's motor stimulant properties at doses studied in mice did not appear to inflate antidepressant-like behavioral test results, as locomotor activity was specifically monitored and found unaffected at sub-stimulant doses (3 mg/kg). This separation of behavioral effects is considered methodologically important in interpreting the antidepressant findings.
The methotrexate-mediated reduction in leukocyte accumulation was completely reversed by the specific adenosine A2 receptor antagonist DMPX, but not affected by an adenosine A1 receptor antagonist, establishing that methotrexate's anti-inflammatory effect on leukocyte migration is mediated through the adenosine A2 receptor subtype. This observation has been used as a pharmacological tool to dissect the immunological mechanisms of methotrexate, widely used in rheumatoid arthritis and other autoimmune diseases. DMPX here functioned as a receptor-characterization probe rather than a therapeutic agent.
The co-administration of DMPX with PDRN (polydeoxyribonucleotide) in an experimental model of acute liver damage resulted in the disappearance of PDRN's anti-inflammatory and anti-apoptotic effects, suggesting that PDRN's hepatoprotective mechanisms are mediated through the adenosine A2A receptor. Again, this study used DMPX as a pharmacological blocking tool to confirm A2A receptor involvement, not as a proposed therapeutic.
DMPX has been used to study its effects on the cell viability of a human gastric cancer cell line and the role of the A2A receptor in elevating cyclic adenosine monophosphate (cAMP) levels. DMPX was shown to be capable of downregulating ABCG2 protein levels in cancer cell lines, which is associated with multidrug resistance. These observations are highly preliminary (cell-line studies) and DMPX has not been investigated clinically for any oncological indication.
DMPX has also been used to study its effects on the potential modulation of motor output elicited by epidural spinal stimulation (ESS), as part of investigations into the physiological role of spinal adenosine A2A receptors in motor circuits. These remain preclinical tool-compound studies.
DMPX's most important scientific contribution has been as a chemical template for the development of more potent and selective A2A antagonists. A series of 8-substituted derivatives of DMPX was synthesized and investigated as A2A adenosine receptor antagonists. A recently developed synthetic procedure starting from 3-propargyl-5,6-diaminouracil proved to be the method of choice for the preparation of this type of xanthine derivatives.
8-Styryl-substituted DMPX derivatives were identified that exhibit high affinity and selectivity for A2A adenosine receptors, including 8-(m-chlorostyryl)-DMPX (CS-DMPX, Ki A2A = 13 nM, 100-fold selective) and 8-(m-bromostyryl)-DMPX (BS-DMPX, Ki A2A = 8 nM, 146-fold selective). These second-generation compounds represent orders-of-magnitude improvements in both affinity and selectivity compared to the parent DMPX molecule, which has a Ki of only 11 μM at the A2A receptor. The medicinal chemistry program that used DMPX as a scaffold ultimately contributed to the development of clinical-stage A2A antagonists.
DMPX has no approved pharmaceutical or dietary supplement form for human use. All dosing information in the scientific literature relates exclusively to preclinical (animal) experiments:
No human dose has been established, studied, or validated. The compound is not present in any pharmacopoeial monograph (USP, European Pharmacopoeia, WHO) as a recognized medicinal or dietary ingredient.
There are no published human safety, tolerability, or pharmacokinetic studies for DMPX. Despite promising laboratory results, clinical studies in humans are limited; the safety profile, optimal dosing, and efficacy of DMPX in nutritional products have not been fully established.
Regulatory classification. All commercial suppliers label DMPX for research use only and explicitly state it is not for human or veterinary use. It is not classified or approved as a dietary ingredient under any recognized regulatory framework (U.S. FDA, EFSA, or others).
Hazard classification (laboratory context). The Sigma-Aldrich safety data sheet classifies DMPX as an Eye Irritant Category 2, Skin Irritant Category 2, and STOT SE Category 3 (specific target organ toxicity, single exposure). These classifications are for laboratory handling of the powder and are not clinical assessments.
Known pharmacological interactions. The interaction between DMPX and coadministered antidepressant drugs was investigated in the mouse pharmacokinetic studies described above. To evaluate whether observed behavioral effects were due to pharmacokinetic/pharmacodynamic interaction, the levels of antidepressants in blood and brain were measured using HPLC; the interaction between DMPX and imipramine was found to be exclusively pharmacodynamic in nature, whereas increased antidepressant activity of escitalopram and reboxetine was at least partly related to pharmacokinetic interaction with DMPX. This suggests DMPX may alter the plasma or brain concentrations of certain co-administered drugs, a finding with direct relevance to potential interaction risks, even if studied only in mice.
A2A receptor biology and potential off-target effects. Given that DMPX has been shown to also interact with the A2B adenosine receptor subtype at concentrations used in in vivo studies, and given the widespread distribution of adenosine receptors across cardiac, vascular, gastrointestinal, renal, and immune tissues, broad systemic effects would be anticipated with any human use — consistent with what is known about non-selective xanthine adenosine antagonists such as theophylline. No specific toxicological studies on DMPX in animals or humans have been published in the peer-reviewed literature accessible for this review.
DMPX's historical scientific importance is as the first pharmacological probe establishing the in vivo feasibility of A2A adenosine receptor antagonism. This work helped lay the conceptual groundwork for a subsequent generation of highly selective A2A antagonists. Several selective antagonists for adenosine A2A receptors are currently under evaluation in clinical trials (phases I to III) to treat Parkinson's disease. Istradefylline (KW-6002), a descendant of this medicinal chemistry program, received regulatory approval in Japan and the United States for PD as an adjunctive therapy. DMPX itself, however, has not followed this trajectory into clinical development.
The totality of published research on DMPX can be characterized as follows:
Health conditions that DMPX may help support.
Body systems that DMPX may help support.
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