TY - JOUR TI - Inhibition of itch by neurokinin 1 receptor (Tacr1) -expressing ON cells in the rostral ventromedial medulla in mice AU - Follansbee, Taylor AU - Domocos, Dan AU - Nguyen, Eileen AU - Nguyen, Amanda AU - Bountouvas, Aristea AU - Velasquez, Lauren AU - Iodi Carstens, Mirela AU - Takanami, Keiko AU - Ross, Sarah E AU - Carstens, Earl A2 - Kuner, Rohini A2 - Wassum, Kate M A2 - Hoon, Mark A2 - Samineni, Vijay K VL - 11 PY - 2022 DA - 2022/08/16 SP - e69626 C1 - eLife 2022;11:e69626 DO - 10.7554/eLife.69626 UR - https://doi.org/10.7554/eLife.69626 AB - The rostral ventromedial medulla (RVM) is important in descending modulation of spinal nociceptive transmission, but it is unclear if the RVM also modulates spinal pruriceptive transmission. RVM ON cells are activated by noxious algesic and pruritic stimuli and are pronociceptive. Many RVM-spinal projection neurons express the neurokinin-1 receptor (Tacr1), and ON-cells are excited by local administration of substance P (SP). We hypothesized that Tacr1-expressing RVM ON cells exert an inhibitory effect on itch opposite to their pronociceptive action. Intramedullary microinjection of SP significantly potentiated RVM ON cells and reduced pruritogen-evoked scratching while producing mild mechanical sensitization. Chemogenetic activation of RVM Tacr1-expressing RVM neurons also reduced acute pruritogen-evoked scratching. Optotagging experiments confirmed RVM Tacr1-expressing neurons to be ON cells. We conclude that Tacr1-expressing ON cells in RVM play a significant role in the modulation of pruriceptive transmission. KW - itch KW - descending modulation KW - pain KW - RVM JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -