Osanetant is a selective antagonist of neurokinin 3 receptor NK3. Neurokinins (tachykinins) are members of a family of at least three neuropeptides, substance P, neurokinin A, and neurokinin B (NKB), with each mediating their biological effects through binding to a preferred G-protein-coupled receptor termed NK1, NK2, or NK3, respectively. All three NK receptors are expressed in regions of the central nervous system that are related to emotion and cognition (i.e., amygdala and hippocampus) and have been linked to various degrees in psychiatric disorders. Neurokinin receptors, including NK3 receptors, are also expressed in the motor and sensory systems of the digestive tract. Osanetant was in clinical trials for both irritable bowel syndrome and schizophrenia.
