Regulation of Itch-Induced Scratching by Nucleus Accumbens Dopamine Receptor-Expressing Neurons

This study investigates the role of dopamine receptor-expressing neurons in the nucleus accumbens (NAc) in regulating itch-induced scratching behavior. The researchers found that neurons expressing dopamine D1 receptors (D1R) in the NAc lateral shell (LaSh) promote scratching, while those expressing D2 receptors (D2R) facilitate the termination of scratching. Using optogenetic manipulations, they demonstrated that NAc LaShD2R neurons inhibit neurons in the lateral parabrachial nucleus (LPBN) to stop scratching. Additionally, dopamine levels in the NAc LaSh were higher during chronic itch compared to acute itch, indicating that increased dopaminergic signaling may contribute to persistent scratching. These findings highlight the neural circuit mechanisms linking reward pathways to itch regulation.