Adenosine receptor antagonists

Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class and is the most commonly consumed psychoactive substance globally. It is mainly used for its eugeroic (wakefulness promoting), ergogenic (physical performance-enhancing), or nootropic (cognitive-enhancing) properties; it is also used recreationally or in social settings. Caffeine acts by blocking the binding of adenosine at a number of adenosine receptor types, inhibiting the centrally depressant effects of adenosine and enhancing the release of acetylcholine. Caffeine has a three-dimensional structure similar to

Theobromine, also known as xantheose, is the principal alkaloid of Theobroma cacao (cacao plant). Theobromine is slightly water-soluble (330 mg/L) with a bitter taste. In industry, theobromine is used as an additive and precursor to some cosmetics. It is found in chocolate and several other foods, including tea (Camellia sinensis), some American hollies (yaupon and guayusa) and the kola nut. It is a white or colourless solid, but commercial samples can appear yellowish.

thumb|right|upright|Theophylline extended-release tablets in Japan Theophylline, also known as 1,3-dimethylxanthine, is a drug that inhibits phosphodiesterase and blocks adenosine receptors. It is used to treat chronic obstructive pulmonary disease (COPD) and asthma. Its pharmacology is similar to other methylxanthine drugs (e.g., theobromine and caffeine). Trace amounts of theophylline are naturally present in tea, coffee, chocolate, yerba mate, guarana, and kola nut.

Fenethylline (BAN, USAN) or fenetylline (INN) is a codrug of amphetamine and theophylline and so a mutual prodrug of both. It is also spelled phenethylline; other names for it are amphetaminoethyltheophylline and amfetyline. The drug was marketed for use as a psychostimulant under the brand names Captagon, Biocapton, and Fitton. The brand name "Captagon" (or in lowercase as "captagon") is often used generically to describe illicitly produced fenethylline.

Aminophylline is a compound of the bronchodilator theophylline with ethylenediamine in 2:1 ratio. The ethylenediamine improves solubility, and the aminophylline is usually found as a dihydrate.

Pentoxifylline, also known as oxpentifylline, is a xanthine derivative used as a drug to treat muscle pain in people with peripheral artery disease. It was approved for medical use in 1984 and is available as generic and sold under many brand names worldwide like Trental.

Paraxanthine, also known as 1,7-dimethylxanthine, is an isomer of theophylline and theobromine, two well-known stimulants found in coffee, tea, and chocolate. It is a member of the xanthine family of alkaloids, which also includes theophylline and theobromine in addition to caffeine.

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IBMX (3-isobutyl-1-methylxanthine), like other methylxanthine derivatives, is both a: competitive non-selective phosphodiesterase inhibitor which raises intracellular cAMP, activates PKA, inhibits TNFα and leukotriene synthesis, and reduces inflammation and innate immunity, and nonselective adenosine receptor antagonist.

Istradefylline, sold under the brand name Nourianz, is a medication used as an add-on treatment to levodopa/carbidopa in adults with Parkinson's disease (PD) experiencing "off" episodes. Istradefylline reduces "off" periods resulting from long-term treatment with the antiparkinson drug levodopa. An "off" episode is a time when a patient's medications are not working well, causing an increase in PD symptoms, such as tremor and difficulty walking.

Diprophylline (INN) or dyphylline (USAN) (trade names Dilor, Lufyllin) is a xanthine derivative with bronchodilator and vasodilator effects. It is used in the treatment of respiratory disorders like asthma, cardiac dyspnea, and bronchitis. It acts as an adenosine receptor antagonist and phosphodiesterase inhibitor.

8-Chlorotheophylline, also known as 1,3-dimethyl-8-chloroxanthine, is a stimulant drug of the xanthine chemical class, with physiological effects similar to caffeine. Its main use is in combination (salt) with diphenhydramine in the antiemetic dimenhydrinate (Dramamine). Diphenhydramine reduces nausea but causes drowsiness, and the stimulant properties of 8-Chlorotheophylline help reduce that side effect.

8-Phenyltheophylline (8-phenyl-1,3-dimethylxanthine, 8-PT) is a drug derived from the xanthine family which acts as a potent and selective antagonist for the adenosine receptors A1 and A2A, but unlike other xanthine derivatives has virtually no activity as a phosphodiesterase inhibitor. It has stimulant effects in animals with similar potency to caffeine. Coincidentally 8-phenyltheophylline has also been found to be a potent and selective inhibitor of the liver enzyme CYP1A2 which makes it likely to cause interactions with other drugs which are normally metabolised by CYP1A2.

Acefylline (INN), also known as 7-theophyllineacetic acid, is a stimulant drug of the xanthine chemical class. It acts as an adenosine receptor antagonist. It is combined with diphenhydramine in the pharmaceutical preparation etanautine to help offset diphenhydramine induced drowsiness.

Bamifylline is a drug of the xanthine chemical class which acts as a selective adenosine A1 receptor antagonist.

Proxyphylline is a xanthine derivative that acts as a cardiac stimulant, vasodilator and bronchodilator.

pharmaceutical drug

Rolofylline (KW-3902) is an experimental diuretic which acts as a selective adenosine A1 receptor antagonist. It was discovered at NovaCardia, Inc. which was purchased by Merck & Co., Inc. in 2007.

Theacrine, also known as 1,3,7,9-tetramethyluric acid, is a purine alkaloid found in cupuaçu (Theobroma grandiflorum) and in a Chinese kucha tea () (Camellia assamica var. kucha). It shows anti-inflammatory and analgesic effects and appears to affect adenosine signalling in a manner similar to caffeine. In kucha leaves, theacrine is synthesized from caffeine in what is thought to be a three-step pathway. Theacrine and caffeine are structurally similar.

8-Cyclopentyl-1,3-dimethylxanthine (8-Cyclopentyltheophylline, 8-CPT, CPX) is a drug which acts as a potent and selective antagonist for the adenosine receptors, with some selectivity for the A1 receptor subtype, as well as a non-selective phosphodiesterase inhibitor. It has stimulant effects in animals with slightly higher potency than caffeine.

Dimethazan (Elidin) is a stimulant drug of the xanthine class related to caffeine and theophylline. It also has tranquilizing and respiratory-stimulating effects and has been sold as an antidepressant.

Reversine, or 2-(4-morpholinoanilino)-6-cyclohexylaminopurine, is a small molecule developed by the group of Peter G. Schultz, used for stem cell dedifferentiation.

Enprofylline (3-propylxanthine) is a xanthine derivative used in the treatment of asthma, which acts as a bronchodilator. It acts primarily as a competitive nonselective phosphodiesterase inhibitor with relatively little activity as a nonselective adenosine receptor antagonist.

Cafedrine (, ), sold under the brand name Akrinor among others, is a chemical linkage of norephedrine and theophylline and is a cardiac stimulant and antihypotensive agent used to increase blood pressure in people with hypotension. It has been marketed in Europe, South Africa, and Indonesia.

CGS-15943 is a drug which acts as a potent and reasonably selective antagonist for the adenosine receptors A1 and A2A, having a Ki of 3.3nM at A2A and 21nM at A1. It was one of the first adenosine receptor antagonists discovered that is not a xanthine derivative, instead being a triazoloquinazoline. Consequently, CGS-15943 has the advantage over most xanthine derivatives that it is not a phosphodiesterase inhibitor, and so has more a specific pharmacological effects profile. It produces similar effects to caffeine in animal studies, though with higher potency.

Etazolate (SQ-20,009, EHT-0202) is an anxiolytic drug which is a pyrazolopyridine derivative and has unique pharmacological properties. It acts as a positive allosteric modulator of the GABAA receptor at the barbiturate binding site, as an adenosine antagonist of the A1 and A2 subtypes, and as a phosphodiesterase inhibitor selective for the PDE4 isoform. It is currently in clinical trials for the treatment of Alzheimer's disease.

Cartazolate (SQ-65,396) is a drug of the pyrazolopyridine class. It acts as a GABAA receptor positive allosteric modulator at the barbiturate binding site of the complex and has anxiolytic effects in animals. It is also known to act as an adenosine antagonist at the A1 and A2 subtypes and as a phosphodiesterase inhibitor. Cartazolate was tested in human clinical trials and was found to be efficacious for anxiety but was never marketed. It was developed by a team at E.R. Squibb and Sons in the 1970s.

Tracazolate (ICI-136,753) is an anxiolytic drug which is used in scientific research. It is a pyrazolopyridine derivative, most closely related to pyrazolopyrimidine drugs such as zaleplon, and is one of a structurally diverse group of drugs known as the nonbenzodiazepines which act at the same receptor targets as benzodiazepines but have distinct chemical structures.

Propentofylline (HWA 285) is a xanthine derivative drug with purported neuroprotective effects.

8-Cyclopentyl-1,3-dipropylxanthine (DPCPX, PD-116,948) is a drug which acts as a potent and selective antagonist for the adenosine A1 receptor. It has high selectivity for A1 over other adenosine receptor subtypes, but as with other xanthine derivatives DPCPX also acts as a phosphodiesterase inhibitor, and is almost as potent as rolipram at inhibiting PDE4. It has been used to study the function of the adenosine A1 receptor in animals, which has been found to be involved in several important functions such as regulation of breathing and activity in various regions of the brain, and DPCPX has a

Theodrenaline (), also known as noradrenalinoethyltheophylline or as noradrenaline theophylline, is a chemical linkage of norepinephrine (noradrenaline) and theophylline used as a cardiac stimulant. It is sometimes combined with cafedrine.

ATL-444 is a drug which acts as a potent and reasonably selective antagonist for the adenosine receptors A1 and A2A. It has been used to study the role of the adenosine receptor system in the reinforcing action of cocaine, as well as the development of some cancers.

SCH-442,416 is a highly selective adenosine A2a subtype receptor antagonist. It is widely used in its 11C radiolabelled form to map the distribution of A2a receptors in the brain, where they are mainly found in the striatum, nucleus accumbens, and olfactory tubercle. Given its distribution in the brain, A2a receptors have been investigated for the treatment of various neurological disorders, and SCH-442,416 has shown promise in treatment of depression, Parkinson's disease, and catalepsy.

MRS-1706 is a selective inverse agonist for the adenosine A2B receptor. It inhibits release of interleukins and has an antiinflammatory effect.