Neuropeptide Y (NPY) Regulation of Nociceptors

March 7, 2012 updated by: Kenneth Hargreaves, The University of Texas Health Science Center at San Antonio

NPY Regulation of Nociceptors in Clinical Inflammation

Neuropeptide Y (NPY) potently inhibits pain neurons in rats, but does this occur in human pain neurons? This hypothesis will be tested using microdialysis probes in patients who elect to have root canal treatment or extraction of thier tooth.

Study Overview

Status

Completed

Conditions

Detailed Description

The ongoing studies in rats indicate that a sympathetically-derived neuropeptide, neuropeptide Y (NPY), potently inhibits the activity of the capsaicin-sensative class of nociceptors (i.e., "pain" neurons). It is not know whether these results, generated from rodent studies, occur in human tissues under normal or inflamed conditions. We plan to test the hypothesis that NPY inhibits the initiation of neurogenic inflammation, as measured by reduced release of substance P, from capsaicin-sensitive class of petidergic neurons innervating normal and inflamed dental pulp. Such actions would be physiologically and clinically significant, since inhibition of exocytosis from peripheral terminals of nociceptive primary afferent fibers would likely alter neurogenic inflammation, local vasodilation and , possibly pain. Our research strategy takes advantage of a uniquely innervated tissue: dental pulp. Application of any physiologic stimulus to human dental pulp, including thermal, osmotic, chemical or mechanical, produces only pain. Thus, virtually all sensory neurons that innervate pulp appear to be nociceptors. Accordingly, application of drugs to pulpal sensory neurons targets a population of sensory neurons consisting predominantly of nociceptors.

The research questions are as follows:

  1. Determine the capsaicin concentration-response curve from evoking the release of immunioreactive substance P (iSP) from normal and inflamed dental pulp.
  2. Determine the effect of NPY on altering basal and capsaisin-evoked release of iSP from normal and inflamed dental pulp.

We will evaluate the hypothesis that NPY inhibits capsaicin-sensitive neurons in humans using microdialysis probes implanted into anesthetized dental pulp, with release of immunoreactive substance P (iSP) as our dependent measure. This study will include patients who have elected to have a root canal procedure performed or to have a tooth extracted.

Study Type

Observational

Enrollment (Actual)

11

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
    • Texas
      • San Antonio, Texas, United States, 78229
        • University of Texas Health Science Center at San Antonio

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

18 years to 50 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Dental Patients

Description

Inclusion Criteria:

  • teeth with diagnosis of normal pulp or irreversible pulpitis
  • mandibular teeth
  • indication for either root canal or extraction of tooth
  • age between 18-50

Exclusion Criteria:

  • history of taking steroids within the last month
  • history of hyperthyroidism, hypertension, asthma, uncontrolled or complicated Type-2 diabetes, drug abuse
  • age less than 18 or greater than 50
  • maxillary teeth

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

  • Observational Models: Case-Control
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Group I
patients with normal or irreversible pulpitis teeth with capsaicin administered at increasing volumes.
Group II
Patients with normal teeth only with capsaicin added at a specific volume only

Collaborators and Investigators

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

Sponsor

The University of Texas Health Science Center at San Antonio

Investigators

  • Principal Investigator: Kenneth M Hargreaves, DDS,PhD, The University of Texas Health Science Center at San Antonio

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

May 1, 2001

Primary Completion (Actual)

May 1, 2008

Study Completion (Actual)

May 1, 2008

Study Registration Dates

First Submitted

January 7, 2008

First Submitted That Met QC Criteria

January 15, 2008

First Posted (Estimate)

January 16, 2008

Study Record Updates

Last Update Posted (Estimate)

March 8, 2012

Last Update Submitted That Met QC Criteria

March 7, 2012

Last Verified

March 1, 2012

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • HSC20010247H

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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