Clinical trial NCT00223366: In Vitro Studies on Pharmacological Regulation and Genetic Risk Factors of Peripheral Human Nociceptors
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
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Pain
Keywords: Pain in teeth
Lead sponsor: The University of Texas Health Science Center at San Antonio
Sponsor class: OTHER
Collaborators: name: National Institutes of Health (NIH)
name: National Institute of Neurological Disorders and Stroke (NINDS)
First posted: 2005-09-22
Enrollment: 2007
Sex: ALL
Minimum age (years): 16
Maximum age (years): 90
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_ONLY
Time perspective: CROSS_SECTIONAL
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.

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

Detailed description: Purpose/Objectives

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.

Eligibility criteria: 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.

Primary outcomes:
measure: Effects of inflammation in periradicular tissues.
timeFrame: Immediately following tooth extraction and dental pulp procurement.
Secondary outcomes:
measure: Altered pain reports.
timeFrame: 24 hour post-tooth extraction.
Other outcomes:
Locations:
city: San Antonio
country: United States
facility: The University of Texas Health Science Center at San Antonio
state: Texas
Study officials:
affiliation: University of Texas Health Science Center at San Antonio, Texas
name: Kenneth M. Hargreaves, DDS, PhD
role: PRINCIPAL_INVESTIGATOR
References: