In this experiment, the investigators would like to test the following:

1. Does acute pain induced by hypertonic injection cause changes in plasma miRNA and protein expression ?
2. Can these canges correlate with the development of local hyperalgesia?
3. How does the plasma miRNA expression change over a duration of 24 hours post pain induction ?
4. Which mRNA targets are potentially affected by acute pain?

Inclusion Criteria:

• Healthy men and women in the age 18-80 years
• Speak and understand English

Exclusion Criteria:

• Acute and chronic pain
• Pregnancy or breastfeeding
• Drug addiction defined as the use of cannabis, opioids or other drugs
• Present or previous 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 antipsychotics and pain killers as well as systemic or topical steroids and anti-inflammatory drugs.
• Skin diseases
• Consumption of alcohol or painkillers 24 hours before the study days and between these
• Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical trials)