L-menthol as a Topical Counter-irritant to TRPA1-induced Neurogenic Inflammation and Pain

High-concentration L-menthol as a Counter-irritant to TRPA1-induced Neurogenic Inflammation, Thermal and Mechanical Hyperalgesia Caused by Trans-cinnamaldehyde

The aim of this study is to quantitatively characterize the effects of L-menthol as a topical counter-irritant on cutaneous pain and hyperalgesia provoked by topical application of the TRPA1-agonist trans-cinnamaldehyde (CA) in healthy human volunteers.

This study is designed as an experimental model in healthy humans.

Inclusion Criteria:

• 18 healthy men and women aged 18-50 years willing to abstain from alcohol, nicotine, caffeine and pain medication 24 hours before experimental sessions

Exclusion Criteria:

• Pregnancy
• Skin disorders (e.g. contact eczema)
• Chronic pain conditions
• Drug addiction defined as the use of cannabis, opioids or other drugs
• Previous neurologic, musculoskeletal or mental illnesses
• Lack of ability to cooperate