Neuromedin B (NMB) is a neuropeptide hormone that functions as a signaling molecule across multiple physiological systems. Primary functions include smooth muscle contraction and regulation of respiratory reflexes, particularly through action on the pre-Botzinger complex to induce sighing [UniProt], and coordination of sneeze responses via NMBR-expressing neurons in the brainstem [UniProt]. NMB also modulates sensory perception, contributing to acute itch induction possibly through dorsal root ganglion neuron activation [UniProt]. In reproductive endocrinology, NMB increases NMBR expression and steroidogenic factors (STAR, CYP11A1, HSD3B1) in Leydig cells, promoting testosterone secretion and cell proliferation [UniProt]. Mechanistically, NMB operates through neuropeptide signaling pathways via receptor binding and cell-cell communication [GO annotations]. Beyond neurological functions, NMB participates in innate immunity against influenza A virus infection by enhancing interferon-alpha expression while reducing IL-6 production 1, and contributes to osteoclast precursor proliferation through positive regulation of CSF1R expression [UniProt]. These diverse functions establish NMB as a pleiotrophic signaling molecule with implications in respiratory physiology, endocrine regulation, immune response, and bone homeostasis.