Activation of sensory nerves in the upper airways by allergic inflammation, surgical intervention, airborne pollutants and tobacco smoke initiates cardiopulmonary and upper airway reflexes. Reflexes and sensations include sneezing, itch, congestion, mucus secretion, bronchospasm, altered respiratory pattern, arterial hypotension and bradycardia. The specific nature of a given reflex response is likely due to the type of upper airway afferent nerve that is activated. However, progress in this area has been limited by a lack of information regarding upper airways sensory nerve subtypes and their mechanisms of activation.
In Aim 1, we will address the novel hypothesis that there are two distinct chemosensitive (nociceptor C-fiber) sensory nerve subtypes innervating the upper airways based on activation profile, neurotransmitter content and the area ofthe mucosa they innervate.
In Aims 2 and 3 we will study the activation of these subt3rpes by key stimulants of upper airways-mediated reflexes. Specifically, in Aim 2, we will address hypotheses relating to the role of transient receptor potential Al (TRPAl) in the activation of upper airways nociceptors. TRPAl receptors are activated by a wide range of exogenous substances including pollutants, foodstuffs and tobacco smoke constituents. TRPAl receptors are also targets for downstream signaling events following G-protein coupled receptor activation (e.g. bradykinin B2 receptors). In addition we present the novel hypothesis that TRPAl receptors are directly activated by the endogenously-produced prostanoid 15-deoxy-deltal2,14-prostaglandin J2, a metabolite of PGD2.
In Aim 3 we will address the hypotheses that specific mast cell mediators effect upper airway nociceptor activity via 2 distinct mechanisms: """"""""activation"""""""" and """"""""altered excitability"""""""". We will also evaluate the mechanisms by which these events occur. We will use a combination of anatomical and electrophysiological techniques to address our hjT)Otheses.

Public Health Relevance

Many of the symptoms of nasal diseases depend on the activation of sensory nerves In the nose. Little is known about these nerves, and as such we have limited options for treating nasal diseases caused by allergens or environmental irritants. We believe that these novel studies will provide essential infonnation for the understanding of nasal reflexes, which could lead to novel targets for treating nasal disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Transition Award (R00)
Project #
5R00HL088520-03
Application #
7935389
Study Section
Special Emphasis Panel (NSS)
Program Officer
Laposky, Aaron D
Project Start
2009-09-20
Project End
2012-07-31
Budget Start
2010-08-01
Budget End
2011-07-31
Support Year
3
Fiscal Year
2010
Total Cost
$243,804
Indirect Cost
Name
University of South Florida
Department
Physiology
Type
Schools of Medicine
DUNS #
069687242
City
Tampa
State
FL
Country
United States
Zip Code
33612
Hadley, Stephen H; Bahia, Parmvir K; Taylor-Clark, Thomas E (2014) Sensory nerve terminal mitochondrial dysfunction induces hyperexcitability in airway nociceptors via protein kinase C. Mol Pharmacol 85:839-48
Nesuashvili, Lika; Hadley, Stephen H; Bahia, Parmvir K et al. (2013) Sensory nerve terminal mitochondrial dysfunction activates airway sensory nerves via transient receptor potential (TRP) channels. Mol Pharmacol 83:1007-19
Hooper, Justin Shane; Hadley, Stephen H; Mathews, Adithya et al. (2013) Store-operated calcium entry in vagal sensory nerves is independent of Orai channels. Brain Res 1503:7-15
Bahia, Parmvir K; Bennett, Eric S; Taylor-Clark, Thomas E (2012) Reductions in external divalent cations evoke novel voltage-gated currents in sensory neurons. PLoS One 7:e31585
McAlexander, M Allen; Taylor-Clark, Thomas (2011) The role of transient receptor potential channels in respiratory symptoms and pathophysiology. Adv Exp Med Biol 704:969-86
Taylor-Clark, Thomas E; Undem, Bradley J (2010) Ozone activates airway nerves via the selective stimulation of TRPA1 ion channels. J Physiol 588:423-33
Taylor-Clark, Thomas E; Nassenstein, Christina; McAlexander, M Allen et al. (2009) TRPA1: a potential target for anti-tussive therapy. Pulm Pharmacol Ther 22:71-4