S-38093

S-38093 is a small molecule drug that acts as a selective histamine H3 receptor antagonist and inverse agonist. It also exhibits antagonistic activity at the sigma-1 (σ1) receptor. The compound was developed for its procognitive and antinociceptive properties, with preclinical studies demonstrating its ability to promote hippocampal neurogenesis, enhance memory performance, improve attention and executive function in animal models of cognitive impairment (including Alzheimer's disease), and exert antihyperalgesic effects in neuropathy models. Mechanistically, S-38093 increases extracellular histamine levels in the brain and facilitates cholinergic transmission in key regions involved in cognition such as the prefrontal cortex and hippocampus. The drug reached Phase 2 clinical trials for Alzheimer's disease but development has been discontinued[1][3][4][5][6][7].