: Effective pain control continues to be a major challenge for clinicians and basic scientists, as the lack of efficacy and/or dose-limiting toxicity of existing pharmacotherapies drive intensive efforts to discover novel analgesic strategies. Studies conducted and published during the previous iteration of this award have contributed to an accumulating body of evidence supporting a nicotinic cholinergic approach to pain management. Notably, prototypical nicotinic analgesic agents have been shown to be antinociceptive in animal models of both inflammatory and neuropathic pain. However, the appreciable CNS toxicity of these agents represents a significant obstacle in realizing this otherwise promising avenue of pain control. In this regard, the preliminary data presented in the present renewal application, taken together with the literature cited, strongly supports our working hypothesis that peripheral nicotinic acetylcholine receptors (nAChRs) are capable of mediating antinociception in response to certain nicotinic agonists. We propose to test this hypothesis by addressing the following specific aims: 1) To quantify and pharmacologically characterize the peripheral antinociceptive effects of nicotinic agonists in animal models of pain. 2) To identify the sensory neuronal nAChR subtypes that are activated to produce peripheral antinociception and inhibit nociceptor activity. 3) To define the cellular mechanisms that underlie the inhibition of nociceptor activity by nicotinic agonists. 4) To evaluate the effects of chronic nicotine treatment on sensory neuronal nAChR expression and nicotinic agonist-induced antinociception. The integrated, multimethodological studies proposed here should help to elucidate peripheral mechanisms of nicotinic analgesia. Such an understanding would provide important information for a rationale to develop a nicotinic cholinergic class of analgesic therapeutics that may have improved efficacy over current treatments without the attendant, CNS-mediated toxicities.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA010510-07
Application #
6522970
Study Section
Special Emphasis Panel (ZRG1-IFCN-5 (06))
Program Officer
Thomas, David A
Project Start
1996-09-10
Project End
2006-07-31
Budget Start
2002-08-01
Budget End
2003-07-31
Support Year
7
Fiscal Year
2002
Total Cost
$289,000
Indirect Cost
Name
University of Texas Health Science Center San Antonio
Department
Dentistry
Type
Schools of Dentistry
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
Price, Theodore J; Flores, Christopher M (2007) Critical evaluation of the colocalization between calcitonin gene-related peptide, substance P, transient receptor potential vanilloid subfamily type 1 immunoreactivities, and isolectin B4 binding in primary afferent neurons of the rat and mouse. J Pain 8:263-72
Dussor, G O; Jones, D J; Hulsebosch, C E et al. (2005) The effects of chemical or surgical deafferentation on [3H]-acetylcholine release from rat spinal cord. Neuroscience 135:1269-76
Dussor, Gregory O; Helesic, Gabriela; Hargreaves, Kenneth M et al. (2004) Cholinergic modulation of nociceptive responses in vivo and neuropeptide release in vitro at the level of the primary sensory neuron. Pain 107:22-32
Dussor, Gregory O; Leong, Anthony S; Gracia, Nicholas B et al. (2003) Potentiation of evoked calcitonin gene-related peptide release from oral mucosa: a potential basis for the pro-inflammatory effects of nicotine. Eur J Neurosci 18:2515-26
Dussor, Gregory O; Price, Theodore J; Flores, Christopher M (2003) Activating transcription factor 3 mRNA is upregulated in primary cultures of trigeminal ganglion neurons. Brain Res Mol Brain Res 118:156-9
Gilbert, S D; Clark, T M; Flores, C M (2001) Antihyperalgesic activity of epibatidine in the formalin model of facial pain. Pain 89:159-65
Flores, C M; Leong, A S; Dussor, G O et al. (2001) Capsaicin-evoked CGRP release from rat buccal mucosa: development of a model system for studying trigeminal mechanisms of neurogenic inflammation. Eur J Neurosci 14:1113-20
Ulrich-Lai, Y M; Flores, C M; Harding-Rose, C A et al. (2001) Capsaicin-evoked release of immunoreactive calcitonin gene-related peptide from rat trigeminal ganglion: evidence for intraganglionic neurotransmission. Pain 91:219-26
Flores, C M; Wilson, S G; Mogil, J S (1999) Pharmacogenetic variability in neuronal nicotinic receptor-mediated antinociception. Pharmacogenetics 9:619-25
Flores, C M; Davila-Garcia, M I; Ulrich, Y M et al. (1997) Differential regulation of neuronal nicotinic receptor binding sites following chronic nicotine administration. J Neurochem 69:2216-9

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