NGF and myeloid sarcoma: In addition, sensitization and upregulation of microglial toll-like receptor 4 (TLR4) signaling activity in the PVN (Tang et al., 2017), ephrin-B2/EphB1 spinal signaling pathway (Theofanous et al., 2020), and nerve growth factor (NGF)–mediated tropomyosin receptor kinase A (TrkA) signaling (Wong et al., 2019) were involved in MS-induced visceral hypersensitivity.