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Neuropeptide Y (NPY) Regulation of Nociceptors

Sponsor
The University of Texas Health Science Center at San Antonio (Other)
Overall Status
Completed
CT.gov ID
NCT00596193
Collaborator
(none)
11
Enrollment
1
Location
84
Duration (Months)
0.1
Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease Intervention/Treatment Phase

    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 Design

    Study Type:
    Observational
    Actual Enrollment :
    11 participants
    Observational Model:
    Case-Control
    Time Perspective:
    Prospective
    Official Title:
    NPY Regulation of Nociceptors in Clinical Inflammation
    Study Start Date :
    May 1, 2001
    Actual Primary Completion Date :
    May 1, 2008
    Actual Study Completion Date :
    May 1, 2008

    Arms and Interventions

    Arm Intervention/Treatment
    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

    Outcome Measures

    Primary Outcome Measures

      Eligibility Criteria

      Criteria

      Ages Eligible for Study:
      18 Years to 50 Years
      Sexes Eligible for Study:
      All
      Accepts Healthy Volunteers:
      Yes
      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

      Contacts and Locations

      Locations

      Site City State Country Postal Code
      1 University of Texas Health Science Center at San Antonio San Antonio Texas United States 78229

      Sponsors and Collaborators

      • 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 Documents (Full-Text)

      None provided.

      More Information

      Publications

      None provided.
      Responsible Party:
      Kenneth Hargreaves, Chair, Dept. of Endodontics, The University of Texas Health Science Center at San Antonio
      ClinicalTrials.gov Identifier:
      NCT00596193
      Other Study ID Numbers:
      • HSC20010247H
      First Posted:
      Jan 16, 2008
      Last Update Posted:
      Mar 8, 2012
      Last Verified:
      Mar 1, 2012
      Keywords provided by Kenneth Hargreaves, Chair, Dept. of Endodontics, The University of Texas Health Science Center at San Antonio
      Hyperalgesia
      nociceptors
      Neurons

      Study Results

      No Results Posted as of Mar 8, 2012