Itch induces conditioned place aversion in mice.

Itch sensation consists of both sensory and emotional components. The molecular and cellular mechanisms underlying the transduction and transmission of itch sensation have been studied extensively in rodents. However, whether itch induces emotional responses in mice still remains unknown. We found that pruritogens induced conditioned place aversion (CPA) in mice, and that the CPA lasted for at least two weeks. Disruption of itch signal transmission by depletion of peripheral sensory fibers expressing TRPV1 (transient receptor potential vanilloid subfamily, member 1) attenuated chloroquine-induced CPA. Consistently, ablation of itch-specific neurons that express gastrin-releasing peptide receptor in the spinal cord also abolished itch-induced CPA, confirming that itch-induced CPA is dependent on the spinal itch circuit. Thus, these results demonstrate that itch can induce CPA in mice, which requires peripheral itch signal inputs.