Transient Receptor Potential Channels (TRP)

July 24, 2026 updated by: Lacy Alexander, Penn State University

Transient Receptor Potential Channels in Human Skin

Neurovascular signaling in the skin associated with stimulation of the transient receptor potential (TRP) channels. These channels are stimulated by both temperature and naturally occurring bioactive agents found in mint, chili peppers, garlic, etc. The aim of the study is to examine how topically applied TRP channel agonists including menthol, capsaicin and camphor impact neurovascular responses in the skin.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

45

Phase

  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Pennsylvania
      • University Park, Pennsylvania, United States, 16802
        • Noll Laboratory

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 18-85 years old.
  • Women will not be pregnant and/or breastfeeding.

Exclusion Criteria:

  • Currently pregnant or breastfeeding
  • Nicotine use (e.g., smoking, chewing tobacco etc.), quantified as more than 100 cigarettes or cigars in a lifetime)
  • Known skin allergies or current rash, skin disease, disorders of pigmentation
  • Diabetes
  • Body mass index >35kg*m-2
  • Using calcium channel blockers
  • Raynaud's syndrome
  • Allergy or hypersensitivity to menthol, camphor, capsaicin or adhesive
  • Regular use (defined as greater than once a week) of topical analgesics that contain menthol, camphor or capsaicin

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Single Group Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Vehicle Gel
Non-active topical gel
Other: Vehicle gel
Inactive vehicle gel
Other Names:
  • Inactive vehicle gel
Experimental: Transient Receptor Potential (M8) Agonist
Topical menthol gel applied once at 10%
Drug: TRPM8 Agonist
menthol gel 4-10%
Other Names:
  • menthol
Experimental: Transient Receptor Potential (V4) Agonist
Topical capsaicin gel applied once at 0.05%
Drug: TRPV4 Agonist
capsaicin gel 0.05-1%%
Other Names:
  • capsaicin
Experimental: Transient Receptor Potential (V1) Agonist
Topical camphor gel applied once at 0.6%
Drug: TRPV1 Agonist
camphor gel 5-20%
Other Names:
  • camphor
Experimental: Transient Receptor Potential M8 V4 V1 Agonist
Topical menthol 10%, capsaicin 0.05%, camphor 0.6% applied once
Drug: TRPM8, TRPV4, TRPV1 Agonists
menthol (4-10%), capsaicin (0.05-1%), camphor (5-20%)
Other Names:
  • menthol, capsaicin, camphor
No Intervention: no gel
no gel comparison

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Skin blood flow during slow local heating
Time Frame: 75 minutes
Laser doppler flowmeter to measure skin blood flow during a slow local heating of the skin
75 minutes
Somatosensory perception
Time Frame: every 5 minutes for 120 minues
heat and cold perception using a visual analog scale
every 5 minutes for 120 minues
algometer measurement
Time Frame: every 30 minutes for 120 minutes
pain pressure thresholds
every 30 minutes for 120 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Penn State University

Investigators

  • Principal Investigator: Lacy Alexander, Ph.D., Penn State University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 17, 2024

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2027

Study Registration Dates

First Submitted

May 24, 2024

First Submitted That Met QC Criteria

May 30, 2024

First Posted (Actual)

June 5, 2024

Study Record Updates

Last Update Posted (Actual)

July 27, 2026

Last Update Submitted That Met QC Criteria

July 24, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 24921

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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