CClinicalTrials.gg
CompletedNCT00596193Updated Mar 8, 2012

Neuropeptide Y (NPY) Regulation of Nociceptors

An observational study in Pain, sponsored by The University of Texas Health Science Center at San Antonio. Completed at 1 site in United States. Open to participants aged 18 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2012-03-08.

Sponsored by The University of Texas Health Science Center at San Antonio · Observational

Study type
Observational
Model
Case-control
Time perspective
Prospective
Enrollment
11
Ages
18 Years to 50 Years
Sex
All
01

Study 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.

Read the 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.

02

Conditions studied

  • Pain

Keywords

  • Hyperalgesia
  • nociceptors
  • Neurons
03

In context

Lead sponsor

The University of Texas Health Science Center at San Antonio is the lead sponsor of 435 studies on the registry; 88 are open to participants now.

Of its 62 completed or terminated interventional studies of FDA-regulated products, 31 (50%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 50 Years
Sexes eligible
All
Accepts healthy volunteers
Yes
Sampling method
Probability sample

Study population

Dental Patients

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

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
05

Study design

Observational model
Case-control
Time perspective
Prospective
Enrollment
11 participants (actual)

Groups and cohorts

  • 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

06

Study locations

1 site
  • University of Texas Health Science Center at San Antonio
    San Antonio, Texas 78229, United States
07

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Mar 8, 2012, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
08

Registry details

Key details

Study ID
NCT00596193
Lead sponsor
The University of Texas Health Science Center at San Antonio
Responsible party
Kenneth Hargreaves (Chair, Dept. of Endodontics, The University of Texas Health Science Center at San Antonio) — Principal investigator
First posted
Jan 16, 2008
Start date
May 2001
Primary completion
May 2008
Completion
May 2008
Last update
Mar 8, 2012

Study contacts

Kenneth M Hargreaves, DDS,PhD
principal investigator · The University of Texas Health Science Center at San Antonio

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Mar 2012. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Start the discussion