gsk-189254 gsk-189254 gsk-189,254 is a potent and selective h3 histamine receptor inverse agonist developed by glaxosmithkline. it has subnanomolar affinity for the h3 receptor (ki = 0.2nm) and selectivity of over 10,000x for h3 over other histamine receptor subtypes. animal studies have shown it to possess not only stimulant and nootropic effects, but also analgesic action suggesting a role for h3 receptors in pain processing in the spinal cord. gsk-189,254 and several other related drugs are currently being investigated as a treatment for alzheimer's disease and other forms of dementia, as well as possible use in the treatment of conditions such as narcolepsy, or neuropathic pain which do not respond well to conventional analgesic drugs. gsk-189254identifiers iupac name 6--n-methylpyridine-3-carboxamide cas number720690-73-3 npubchem cid9798547chemspider7974313 nunii5t4tx6co53chemblchembl517140 ncomptox dashboard (epa)dtxsid801005982 chemical and physical dataformulac21h25n3o2molar mass351.450 g·mol−13d model (jsmol)interactive image smiles c4cc1ccn(c3ccc3)ccc1cc4oc(cc2)ncc2c(=o)nc inchi inchi=1s/c21h25n3o2/c1-22-21(25)17-6-8-20(23-14-17)26-19-7-5-15-9-11-24(18-3-2-4-18)12-10-16(15)13-19/h5-8,13-14,18h,2-4,9-12h2,1h3,(h,22,25) nkey:wrohewwocprmia-uhfffaoysa-n n ny (what is this?) (verify)