ITCH
Conditions
Brief summary
Previous research has demonstrated that itch and pain share several underlying neural pathways and signaling molecules. Understanding these common mechanisms is important for developing more effective therapeutic strategies targeting both sensations. Mepyramine, an antihistamine, has been reported to exert effects on both itch and pain perception. In this study, we aim to investigate these effects using established experimental models of itch and pain. Itch will be induced using histamine, a naturally occurring substance in the human body, and spicules from the plant Mucuna pruriens (cowhage), while electrical stimulation will be used to assess pain-related responses. By combining these experimental approaches, we aim to better understand how mepyramine influences different sensory mechanisms. The overall purpose of this study is to evaluate the effects of mepyramine on experimentally induced itch and pain in healthy volunteers.
Interventions
DRUGMepyramine cream
Mepyramine cream 2%
One drop of histamine will be applied on the selected areas and pierced with a lancet.
About 30 spicules will be applied on the selected areas and inserted manually
Sponsors
Aalborg University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
In each participant, the same cream will be applied. After the cream removal, itch will be induced using histamine and cowhage.
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy men and women aged 18-60 years * Speak and understand English
Exclusion criteria
* Pregnancy or lactation * Drug addiction defined as any use of cannabis, opioids, or other drugs that may cause addiction. * History of peripheral or chronic pain conditions, neuropathy, neurological, dermatological, or psychiatric diagnoses that may affect the results. * Moles, wounds, scars, or tattoos in the area to be treated or tested * Current use of medications that may affect the trial such as antihistamines, painkillers, antidepressants, or anticonvulsants * Use of antihistamines should be discontinued 72 hours before the experiment and all topical agents and emollients should be discontinued 24 hours before the experiment. * Application of moisturizing lotion of the volar site of the forearms (24 hours before study start) * Previous traumatic experience of an electrical accident * Participation in any other research projects/studies 7 days before study start * Known allergy/intolerance to mepyramine * The subject is assessed as unable to engage in the necessary cooperation required by the study
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Measuring itch by computerized Visual Analog Scale Scoring | During Histamine/cowhage application | We will ask the subjects to rate the sensation of itch on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates |
| Superficial blood perfusion | Before pruritogen application | — |
| Perception threshold tracking model (PTT) | Before cream application | — |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mechanically evoked itch (MEI) | 2 minute after pruritogen removal | MEI is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 miliNewton of force). |
| Mechanical Pain Thresholds (MPT) | 5 minute after pruritogen removal | This test is conducted using a pinprick set. The set consists of 7 needles each with a diameter of 0.6 mm and different force applications: 8, 16, 32, 64, 128, 256, and 512 mN. |
| Mechanical Pain Sensitivity (MPS) | 8 minute after pruritogen removal | This test is conducted with the same pinprick set used to test the MPT. |
| Cold Detection Thresholds (CDT) | 10 minute after pruritogen removal | The tests of thermal sensation will all be conducted using a TSA2 (Medoc Ltd, Israel) thermal sensory testing device |
| Warm Detection Thresholds (WDT) | 10 minute after pruritogen removal | The tests of thermal sensation will all be conducted using a TSA2 (Medoc Ltd, Israel) thermal sensory testing device |
| Cold Pain Thresholds (CPT) | 10 minute after pruritogen removal | The tests of thermal sensation will all be conducted using a TSA2 (Medoc Ltd, Israel) thermal sensory testing device |
| Heat Pain Thresholds (HPT) | 10 minute after pruritogen removal | The tests of thermal sensation will all be conducted using a TSA2 (Medoc Ltd, Israel) thermal sensory testing device |
| Pain to Supra-threshold Heat Stimuli (STHS) | 10 minute after pruritogen removal | The tests of thermal sensation will all be conducted using a TSA2 (Medoc Ltd, Israel) thermal sensory testing device |
Countries
Denmark
Outcome results
None listed