Proxyfan Explained

Proxyfan is a histamine H₃ receptor ligand which is a "protean agonist", producing different effects ranging from full agonist, to antagonist, to inverse agonist in different tissues, depending on the level of constitutive activity of the histamine H₃ receptor. This gives it a complex activity profile in vivo which has proven useful for scientific research.^{[1] [2] [3] [4] [5] [6] [7]}

References

1. Morisset S, Rouleau A, Ligneau X, Gbahou F, Tardivel-Lacombe J, Stark H, Schunack W, Ganellin CR, Schwartz JC, Arrang JM. High constitutive activity of native H3 receptors regulates histamine neurons in brain. Nature. 2000 Dec 14;408(6814):860-4.
2. Fox GB, Pan JB, Esbenshade TA, Bitner RS, Nikkel AL, Miller T, Kang CH, Bennani YL, Black LA, Faghih R, Hancock AA, Decker MW. Differential in vivo effects of H3 receptor ligands in a new mouse dipsogenia model. Pharmacology Biochemistry and Behavior. 2002 Jun;72(3):741-50.
3. Gbahou F, Rouleau A, Morisset S, Parmentier R, Crochet S, Lin JS, Ligneau X, Tardivel-Lacombe J, Stark H, Schunack W, Ganellin CR, Schwartz JC, Arrang JM. Protean agonism at histamine H3 receptors in vitro and in vivo. Proceedings of the National Academy of Sciences USA. 2003 Sep 16;100(19):11086-91.
4. Baldi E, Bucherelli C, Schunack W, Cenni G, Blandina P, Passani MB. The H3 receptor protean agonist proxyfan enhances the expression of fear memory in the rat. Neuropharmacology. 2005 Feb;48(2):246-51.
5. Krueger KM, Witte DG, Ireland-Denny L, Miller TR, Baranowski JL, Buckner S, Milicic I, Esbenshade TA, Hancock AA. G protein-dependent pharmacology of histamine H3 receptor ligands: evidence for heterogeneous active state receptor conformations. Journal of Pharmacology and Experimental Therapeutics. 2005 Jul;314(1):271-81.
6. Arrang JM, Morisset S, Gbahou F. Constitutive activity of the histamine H3 receptor. Trends in Pharmacological Sciences. 2007 Jul;28(7):350-7.
7. Baker JG. Antagonist affinity measurements at the Gi-coupled human histamine H3 receptor expressed in CHO cells. BMC Pharmacology. 2008 Jun 6;8:9.