sentences:  Cipralisant seemed to be well tolerated during early testing, entering Phase II trials for ADHD in 2000.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 functional selectivity and stimulating one type of G-protein coupled pathway while failing to activate other intracellular pathways.