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In Vitro Studies on Pharmacological Regulation and Genetic Risk Factors of Peripheral Human Nociceptors

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ClinicalTrials.gov Identifier: NCT00223366
Recruitment Status : Active, not recruiting
First Posted : September 22, 2005
Last Update Posted : October 25, 2017
Information provided by (Responsible Party):

Study Description
Brief Summary:
This protocol is for a number of in vitro studies using human surgical biopsies and evaluating the pharmacology and genetics of human nociceptors ("pain detecting") neurons

Condition or disease

Detailed Description:


a. Specific Aims Specific Aim 1: Characterize in humans the effects of inflammation and neuronal degeneration on peripheral levels of NPY, and related Y receptors (Y1, Y2, Y5) in periradicular tissue.

Specific Aim 2: Determine whether NPY inhibits neurosecretion from peripheral terminals of capsaicin-sensitive neurons innervating normal versus inflamed tissue.

Specific Aim 3: Determine whether peripheral administration of NPY is analgesic and/or anti-allodynic in patients experiencing spontaneous pain and mechanical allodynia in a clinical model of inflammation with associated neuronal degeneration.

Specific Aim 4: Evaluate whether population characteristics are associated with altered pain reports. First, we will determine whether patients with the C1128 single nucleotide polymorphism (SNP) of the PreProNPY gene, whose phenotype confers substantially augmented peripheral NPY neurosecretion, report less pain compared with patients without this genetic polymorphism. Second, we will determine whether ethnic/cultural factors associated with an underserved minority population (Hispanics in the San Antonio area) are associated with altered pain reports.

Study Design

Study Type : Observational
Estimated Enrollment : 2000 participants
Observational Model: Case-Only
Time Perspective: Cross-Sectional
Official Title: Studies on Normal and Inflamed Dental Pulp, NPY Regulation of Peripheral Human Nociceptors, Peripheral Mechanisms of Opioid Analgesia, Cannabinoid-induced Desensitization of TRPV1 Receptors Adrenergic Modulation of Trigeminal Nociceptors
Actual Study Start Date : October 2001
Estimated Primary Completion Date : August 2019
Estimated Study Completion Date : August 2019
Groups and Cohorts

Outcome Measures

Primary Outcome Measures :
  1. Effects of inflammation in periradicular tissues. [ Time Frame: Immediately following tooth extraction and dental pulp procurement. ]
    Extracted human teeth are sectioned to obtain the crown dental pulp which is placed in a well plate. The pulp is moved every twenty minutes through proprietary substances for a total of 60 to 120 minutes depending on the specific experiment. After each 20 minute fraction, the buffer solution in each well plate is collected, labeled and placed in the -80 freezer along with the pulp sample.

Secondary Outcome Measures :
  1. Altered pain reports. [ Time Frame: 24 hour post-tooth extraction. ]
    Patients provide perceived pain within the first 24 hours post-extraction via a take-home pain postcard. The postcard has a Visual Analog Scale pain graft that the patient marks and returns via mail.

Biospecimen Retention:   Samples With DNA
Whole blood, serum, sputum, oral mucosa tissue, teeth

Eligibility Criteria

Information from the National Library of Medicine

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Ages Eligible for Study:   16 Years to 90 Years   (Child, Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Healthy volunteers between ages 16-90 y.o. presenting to the dental clinics within the University Health Science Center San Antonio for extraction of teeth.

Inclusion Criteria:

  • Willingness to participate; identified indication to have a tooth extraction; 16-90 years old; diagnosis of normal pulp; or diagnosis of irreversible pulpitis requiring a symptom of spontaneous pain and positive and lingering response to pulp vitality test.

Exclusion Criteria:

  • History of taking steroids within the last month; history of taking analgesics in the last four hours.
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00223366

United States, Texas
The 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
National Institutes of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Principal Investigator: Kenneth M. Hargreaves, DDS, PhD University of Texas Health Science Center at San Antonio, Texas
More Information

Responsible Party: Kenneth Hargreaves, Chair, Dept. of Endodontics, The University of Texas Health Science Center at San Antonio
ClinicalTrials.gov Identifier: NCT00223366     History of Changes
Other Study ID Numbers: HSC20020071H
R01NS058655 ( U.S. NIH Grant/Contract )
First Posted: September 22, 2005    Key Record Dates
Last Update Posted: October 25, 2017
Last Verified: October 2017

Keywords provided by Kenneth Hargreaves, The University of Texas Health Science Center at San Antonio:
Pain in teeth