Cipralisant (GT-2331, tentative trade name Perceptin) is an extremely potent histamine H₃ receptor ligand originally developed by Gliatech. Cipralisant was initially classified as a selective H₃

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...

, but newer research (2005) suggests also

agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...

properties, i. e.

functional selectivity Functional selectivity (or “agonist trafficking”, “biased agonism”, “biased signaling”, "ligand bias" and “differential engagement”) is the ligand-dependent selectivity for certain signal transduction pathways relative to a referen ...

. Cipralisant seemed to be well tolerated during early testing, entering Phase II trials for

ADHD Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inapp ...

in 2000.Evaluate group
Gliatech Announces Initiation of Perceptin Phase II Clinical Trial
The relatively recent cloning of human H₃ receptor, as well as the discovery of its constitutive activity provided the ability to better assess the activity of H₃ receptor ligands. Consequently, cipralisant was reassessed as an H₃ receptor agonist in human and rat recombinant systems, showing

and stimulating one type of G-protein coupled pathway while failing to activate other intracellular pathways. Gliatech filed for bankruptcy in 2002, and its intellectual property was inherited by

Merck Merck refers primarily to the German Merck family and three companies founded by the family, including: * the Merck Group, a German chemical, pharmaceutical and life sciences company founded in 1668 ** Merck Serono (known as EMD Serono in the Unite ...

. The development of cipralisant seems to have been suspended since 2003 but research is ongoing, and recently it has been shown that it is the (1''S'',2''S'')-enantiomer which is the biologically active one.

References

Cyclopropanes Histamine agonists Imidazoles {{nervous-system-drug-stub