Characterization of New Human Models of Non-histaminergic Itch and Their Interaction With the TRPM8 Receptor

Characterization of New Human Models of Non-histaminergic Itch and Their Interaction With the TRPM8 Receptor

In this experiment the investigators would like to assess if papain induces an itch sensation comparable to the itch sensation induced by cowhage and to confirm that the mechanism of action of papain follows the non-histaminergic pathway.

Inclusion Criteria:

• Healthy men and women
• 18-60 years
• Speak and understand English

Exclusion Criteria:

• Pregnancy or lactation
• Drug addiction defined as any use of cannabis, opioids or other addictive drugs
• Previous or current history of neurological, dermatological, immunological musculoskeletal, cardiac disorder or mental illnesses that may affect the results (e.g. neuropathy, muscular pain in the upper extremities, etc.).
• Lack of ability to cooperate
• Current use of medications that may affect the trial such as antihistamines, antipsychotics and pain killers, as well as systemic or topical steroids.
• Skin diseases
• Moles, scars or tattoos in the area to be treated or tested.
• Hypersensitivity to papaya and mango fruit, cashew nuts, rubber latex
• Consumption of alcohol or painkillers 24 hours before the study days and between these
• Acute or chronic pain
• Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical trials)