Peripheral and central p38 MAPK mediates capsaicin-induced hyperalgesia

Area of Science:

• Neuroscience
• Molecular Biology
• Pharmacology

Background:

• The stress-activated mitogen-activated protein kinase (MAPK) p38 is recognized as a key mediator in pain pathways.
• Understanding the specific roles of p38 MAPK in pain modulation is crucial for developing effective pain therapies.

Purpose of the Study:

• To investigate the involvement of peripheral and spinal p38 MAPK in capsaicin-induced thermal hyperalgesia.
• To evaluate the efficacy of the p38 MAPK inhibitor, SD-282, in mitigating pain responses.

Main Methods:

• Topical capsaicin application to induce thermal hyperalgesia in a rodent model.
• Administration of the p38 MAPK inhibitor SD-282 via systemic, local peripheral, and intrathecal routes.
• Measurement of p38 MAPK phosphorylation and calcitonin gene-related peptide (CGRP) release.

Main Results:

• Topical capsaicin induced time-dependent phosphorylation of p38 MAPK in the hindpaw skin and lumbar spinal cord.
• Systemic, peripheral, and central administration of SD-282 significantly attenuated capsaicin-induced thermal hyperalgesia in a dose-dependent manner.
• SD-282 reduced capsaicin-induced CGRP release in vitro, indicating an effect on peripheral nerve function.

Conclusions:

• p38 MAPK plays a significant role in the development of hyperalgesic states.
• The p38 MAPK pathway mediates pain signaling both centrally within the spinal cord and peripherally in sensory C fibers.
• Inhibition of p38 MAPK presents a potential therapeutic strategy for managing inflammatory pain conditions.