Neuronal Panx1 drives peripheral sensitization in experimental plantar inflammatory pain

Area of Science:

• Neuroscience
• Pain Research
• Molecular Biology

Background:

• Pannexin1 (Panx1) channel protein is linked to chronic pain, but its precise role and mechanisms are not fully understood.
• Understanding Panx1's function is crucial for developing targeted pain therapies.

Purpose of the Study:

• To investigate the specific roles of neuronal and glial Pannexin1 (Panx1) in the development of inflammatory pain.
• To elucidate the cellular and molecular mechanisms by which Panx1 influences pain sensitivity and neuronal function.

Main Methods:

• Utilized wild-type and various Pannexin1 knockout mouse models (global, neuron-specific, glia-specific).
• Assessed pain sensitivity using the von Frey test after complete Freund's adjuvant (CFA) injection.
• Employed qRT-PCR, confocal microscopy, electrophysiology, dye uptake assays, and calcium imaging to analyze Panx1 expression, neuronal excitability, and signaling pathways.

Main Results:

• Global or neuron-specific Panx1 deletion significantly reduced pain sensitivity following CFA stimuli.
• Panx1 was found to enhance neurogenesis and neuronal excitability, partly through the Wnt/β-catenin pathway.
• Panx1 channels increased DRG neuron and satellite glial cell responses to ATP, indicating a role in heightened neuronal excitability.
• Neuronal Panx1 expression was significantly higher in DRG compared to TG.

Conclusions:

• Neuronal Pannexin1 (Panx1) is a key mediator of peripheral inflammatory pain sensitivity via cell-autonomous effects on neuronal excitability.
• Glial Panx1 appears to have a more significant role in orofacial inflammatory pain, suggesting cell-type-specific functions in different pain models.
• Differential expression of Panx1 in neurons and glial cells likely contributes to distinct roles in various pain conditions.