Prelimbic cortex-nucleus accumbens core projection positively regulates itch and itch-related aversion.

Itch is one of the most common clinical symptoms in patients with diseases of the skin, liver, or kidney, and it strongly triggers aversive emotion and scratching behavior. Previous studies have confirmed the role of the prelimbic cortex (Prl) and the nucleus accumbens core (NAcC), which are reward and motivation regulatory centers, in the regulation of itch. However, it is currently unclear whether the Prl-NAcC projection, an important pathway connecting these two brain regions, is involved in the regulation of itch and its associated negative emotions. In this study, rat models of acute neck and cheek itch were established by subcutaneous injection of 5-HT, compound 48/80, or chloroquine. Immunofluorescence experiments determined that the number of c-Fos-immunopositive neurons in the Prl increased during acute itch. Chemogenetic inhibition of Prl glutamatergic neurons or Prl-NAcC glutamatergic projections can inhibit both histaminergic and nonhistaminergic itch-scratching behaviors and rectify the itch-related conditioned place aversion (CPA) behavior associated with nonhistaminergic itch. The Prl-NAcC projection may play an important role in the positive regulation of itch-scratching behavior by mediating the negative emotions related to itch.

The microrheological changes in the course of erythrocyte senescence after phenylhydrazine injection.

To study the microrheological characteristics of RBCs during erythrocyte senescence in vivo, an anemia model of rabbit induced by phenylhydrazine injection was developed. Measurements of the hematocrit, the deformation indexes, the blood viscosity and the sedimentation, etc. were performed in vivo for more than 60 days in the processes of RBC senescence. Obvious changes in the RBC's rheological characteristics were found in this senescent model. Compared with our previously developed Wen's model [1,2] in which the entire RBC population was nearly synchronously produced following the induction of spherocytic anemia in the rabbit with antibody serum, the changes of RBC microrheological characteristics for this model showed approximately the same tendency, although Wen's model with antibody serum was much better in its ability to simulation of the nearly normal physiological conditions than the present one with phenylhydrazine injection. Hence, the present model can serve as a model of RBC senescence under abnormal physiological conditions.