Editing Adenosine (section)

== Drug interactions ==
[[Dipyridamole]] potentiates the action of adenosine, requiring the use of lower doses.

[[File:Caffeine and adenosine.svg|class=skin-invert-image|thumb|right|350px|[[Caffeine]]'s principal mode of action is as an [[Receptor antagonist|antagonist]] of adenosine receptors in the brain.<ref>{{cite journal | vauthors = Saygin D, Tabib T, Bittar HE, Valenzi E, Sembrat J, Chan SY, Rojas M, Lafyatis R | title = Transcriptional profiling of lung cell populations in idiopathic pulmonary arterial hypertension | journal = Pulmonary Circulation | volume = 10 | issue = 1 | pages = 1–15 | date = 2020 | pmid = 32166015 | doi = 10.1177/2045894020908782 | pmc = 7052475 }}</ref>]]
[[Methylxanthines]] (e.g. [[caffeine]] found in coffee, [[theophylline]] found in tea, or [[theobromine]] found in chocolate) have a [[purine]] structure and bind to some of the same receptors as adenosine.<ref>{{Cite journal | vauthors = Ribeiro JA, Sebastião AM | title = Caffeine and adenosine | journal = Journal of Alzheimer's Disease | volume = 20 | issue = Suppl 1 | pages = S3-15 | year = 2010 | pmid = 20164566 | doi = 10.3233/JAD-2010-1379 | doi-access = free | hdl = 10451/6361 | hdl-access = free }}</ref> Methylxanthines act as competitive antagonists of adenosine and can blunt its pharmacological effects.<ref>{{Cite web| title=Vitamin B4 |publisher=R&S Pharmchem |url=http://www.rspharmchem.com/vitamin-b4.htm |date=April 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110715213918/http://www.rspharmchem.com/vitamin-b4.htm |archive-date= 2011-07-15 }}</ref> Individuals taking large quantities of methylxanthines may require increased doses of adenosine.

[[Caffeine]] acts by blocking binding of adenosine to the [[adenosine A1 receptor|adenosine A<sub>1</sub> receptor]], which enhances release of the neurotransmitter [[acetylcholine]].<ref>{{Cite journal | vauthors = Carter AJ, O'Connor WT, Carter MJ, Ungerstedt U | title = Caffeine enhances acetylcholine release in the hippocampus in vivo by a selective interaction with adenosine A1 receptors | journal = The Journal of Pharmacology and Experimental Therapeutics | volume = 273 | issue = 2 | pages = 637–642 | date = May 1995 | doi = 10.1016/S0022-3565(25)09521-7 | pmid = 7752065 }}</ref> Caffeine also increases cyclic AMP levels through nonselective inhibition of phosphodiesterase.<ref>{{Cite journal | vauthors = Faudone G, Arifi S, Merk D | title = The Medicinal Chemistry of Caffeine | journal = Journal of Medicinal Chemistry | volume = 64 | issue = 11 | pages = 7156–7178 | date = June 2021 | pmid = 34019396 | doi = 10.1021/acs.jmedchem.1c00261 | s2cid = 235094871 }}</ref> "Caffeine has a three-dimensional structure similar to that of adenosine," which allows it to bind and block its receptors.<ref>{{Cite book | vauthors = Hillis DM, Sadava D, Hill RW, Price MV | title = Principles of Life | edition = 2 | pages = 102–103 | year = 2015 | publisher = Macmillan Learning | isbn = 978-1-4641-8652-3 }}</ref>