TAC3 encodes tachykinin 3 (neurokinin B), a neuropeptide ligand for the G protein-coupled receptor TACR3 that mediates reproductive and neural functions. TAC3 activates TACR3 through two primary signaling pathways: phospholipase C-dependent hydrolysis of phosphatidylinositol 1 and adenylate cyclase activation leading to increased intracellular cAMP 2. As a critical central regulator of gonadal function, TAC3/TACR3 signaling is essential for controlling pulsatile gonadotropin-releasing hormone release and puberty onset 3. TAC3 expression is developmentally regulated by the NRSF transcription factor family, with implications for both normal neural development and epilepsy pathogenesis 4. In the human nervous system, TAC3 marks a distinct striatal interneuron population in the dorsal striatum 56. Clinically, mutations in TAC3 and TACR3 cause hypogonadotropic hypogonadism with or without anosmia, representing major genetic contributors alongside GNRHR mutations 7. Genetic variants in TAC3, particularly the A63P polymorphism, are associated with altered puberty timing in populations 8. These findings establish TAC3 as a fundamental regulator of the hypothalamic-pituitary-gonadal axis with emerging roles in neural circuit development.