UR-PI376 is a histamine H4 receptor agonist (hH4R agonist) (pEC50 = 7.47, alpha = 0.93), with low activity for hH1R and hH2R and significant selectivity for hH3R (pKB = 6.00, alpha =- 0.28), as in stable-use a membrane preparation of hH(x)R-expressing Sf9 cells for state GTPase detection.