A prefrontal peptidergic circuit for psychogenic itch

Area of Science:

• Neuroscience
• Psychology
• Dermatology

Background:

• Psychological stress can trigger itch sensations without external stimuli.
• The neural mechanisms underlying stress-induced itch remain largely unknown.

Purpose of the Study:

• To investigate the role of the medial prefrontal cortex (mPFC) in mediating stress-induced itch.
• To identify the specific neural circuits and molecular pathways involved.

Main Methods:

• Utilized chronic restraint stress models in mice.
• Measured gastrin-releasing peptide (GRP) levels and neuronal activity in the mPFC.
• Employed microinjections, neuronal ablation, and optogenetics to manipulate the GRP/GRP receptor (GRPR) pathway.

Main Results:

• Stress increased GRP release and GRPR neuron activity in the mPFC.
• GRP microinjection into the mPFC induced scratching; GRPR neuron ablation abolished it.
• Optogenetic activation of the GRP-GRPR circuit elicited scratching, while silencing it reduced scratching.

Conclusions:

• A central peptidergic circuit in the mPFC, involving GRP and GRPR neurons, mediates stress-induced itch.
• This pathway represents a critical neural substrate for psychogenic itch.