Characterization of BAM8-22 as a New Surrogate Model of Non-histaminergic Itch

Study Overview
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Brief Summary
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With this experiment, the experimenter wish to asses if substance BAM8-22 (Bovine Adrenal Medulla) induce non-histaminergic itch.

Detailed Description
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With this experiment, the experimenter wish to establish if the substance BAM8-22 (Bovine Adrenal Medulla) induce a non-histaminergic itch by using the antihistamine Doxepin. The experimenter will also compare itch and the response to antihistamine of BAM8-22, histamine and cowhage.

Official Title
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Characterization of Bovine Adrenal Medulla (BAM8-22) as a New Surrogate Model of Non-histaminergic Itch

Conditions
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Itch

Intervention / Treatment
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* Drug: BAM8-22
* Drug: Histamine
* Drug: Cowhage (Mucuna Pruriens)
* Drug: Doxepin


Participation Criteria
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Eligibility Criteria
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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 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.) Moles, wounds, scars or tattoos in the area to be treated or tested Lack of ability to cooperate • Current use of medications that may affect the trial such as antihistamines and pain killers. Skin diseases 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)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Sequential Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: doxepin<br>Drug: Doxepin + BAM8-22 Doxepin will be applied for 1.5 hrs followed by the application of BAM8-22. 20 µl of BAM8-22 will be applied to a previously determined area on the volar forearm followed by a prick through the drop Drug: Doxepin + Histamine Doxepin will be applied for 1.5 hrs followed by the application of Histamine. 20 µl of histamine will be applied to a previously determined area on the volar forearm followed by a prick through the drop Drug: Doxepin + Cowhage Doxepin will be applied for 1.5 hrs followed by the application of cowhage. 25/35 spicules of cowhage will be inserted in the skin through a gentle rubbing on a previously determined area on the volar forearm followed by a prick through the drop Drug: Doxepin + Placebo Doxepin will be applied for 1.5 hrs followed by the application of placebo. 20 µl of placebo will be applied to a previously determined area on the volar forearm followed by a prick through the drop | Drug: BAM8-22<br>* Bovine Adrenal Medulla will be applied to 2 previously determined area on the volar forearm (one alone and one in combination with doxepin)<br>Drug: Histamine<br>* histamine will be applied to 2 previously determined area on the volar forearm (one alone and one in combination with doxepin)<br>Drug: Cowhage (Mucuna Pruriens)<br>* cowhage spicules will be applied to 2 previously determined area on the volar forearm (one alone and one in combination with doxepin)<br>Drug: Doxepin<br>* Doxepin cream (antihistamine) will be applied in 4 areas on the volar forearm<br>|
| Experimental: itch<br>Drug: BAM8-22 20 µl of BAM8-22 will be applied to a previously determined area on the volar forearm followed by a prick through the drop Drug: Histamine 20 µl of histamine will be applied to a previously determined area on the volar forearm followed by a prick through the drop Drug: Cowhage 25/35 spicules of cowhage will be inserted in the skin through a gentle rubbing on a previously determined area on the volar forearm followed by a prick through the drop Drug: Placebo 20 µl of placebo will be applied to a previously determined area on the volar forearm followed by a prick through the drop | Drug: BAM8-22<br>* Bovine Adrenal Medulla will be applied to 2 previously determined area on the volar forearm (one alone and one in combination with doxepin)<br>Drug: Histamine<br>* histamine will be applied to 2 previously determined area on the volar forearm (one alone and one in combination with doxepin)<br>Drug: Cowhage (Mucuna Pruriens)<br>* cowhage spicules will be applied to 2 previously determined area on the volar forearm (one alone and one in combination with doxepin)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| superficial blood perfusion | is measured by a speckle contrast imager (FLPI, Moor Instruments, England) | change from baseline, up to 10 minutes after the first session | 
| Warm Detection Threshold, and Heat Pain threshold | the tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device | change from baseline, up to 10 minutes after the first session | 
| Cold Detection Threshold and Cold Pain threshold | the tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device | change from baseline, up to 10 minutes after the first session | 
| Pain supra-threshold heat Stimuli | the tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device | change from baseline, up to 10 minutes after the first session | 
| hyperknesis (abnormal pruriceptive state) | is measured by using a mildly pruritic, non-painful von Frey filaments of a predetermined intensity (generally 5-30 milliNewton of force) | change from baseline, up to 10 minutes after the first session | 
| mechanical pain threshold and sensitivity | is performed using a pin-prick set (Aalborg University). The set consists of 8 needles each having a diameter of 0,6 mm and different force applications | change from baseline, up to 10 minutes after the first session | 
| itch rating | the subject will rate the itch for 10 minutes by using a visual analog scale (VAS) on a tablet. this scale goes from 0 to 100. 0 indicates no itch and 100 indicates worst imaginable itch | change from baseline, up to 10 minutes after the first session | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pain rating | the subject will rate the pain for 10 minutes by using a visual analog scale (VAS) on a tablet. this scale goes from 0 to 100. 0 indicates no pain and 100 indicates worst imaginable pain | change from baseline, up to 10 minutes after the first session |