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Allergen and BDNF‐induced TRP Channel Expression in Nodose Cough‐fiber Neurons
Author(s) -
Lieu TinaMarie,
Undem Bradley J
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.864.14
Subject(s) - trpv1 , tropomyosin receptor kinase b , tropomyosin receptor kinase a , nodose ganglion , trpm8 , medicine , agonist , receptor , endocrinology , capsaicin , ovalbumin , chemistry , neurotrophin , immunology , neurotrophic factors , vagus nerve , transient receptor potential channel , immune system , stimulation
We evaluated the effect of allergic inflammation on TRPV1 and TRPA1 expression in vagal nodose afferent Aδ “cough fibers” innervating the guinea pig trachea. Actively sensitized guinea pigs were exposed to ovalbumin, (OVA) via aerosol for three days. The nodose neurons innervating the trachea were identified via a standard retrograde trace dye injected into the tracheal wall 3 weeks earlier. Gene expression in indentified neurons was evaluated using single cell RT‐PCR methods. Relatively few trachea Aδ cough receptor neurons express TRPV1 mRNA (5–20% in a given ganglion). One day following the last OVA exposure, greater than 65% of the neurons expressed TRPV1 (P<0.01, χ2). Likewise, allergen exposure nearly doubled the % of cough receptor neurons expressing TRPA1 mRNA (P<0.01). We next characterized the neurotrophin receptor expression in these nodose “cough receptor” neurons. Over 80% of them expressed TRKB, but few expressed either TRKA or TRKC. We therefore went on to test whether BDNF (an agonist for TRKB) could mimic the neuroplasticity noted with allergen challenge. Local application of BDNF (200ng/ml) mimicked the effect of allergen challenge, in that over 65% of the nodose tracheal neurons were induced to express TRPV1 (P<0.01). BDNF did not increase the % of neurons expressing TRPA1. Allergen‐induced TRPA1 and TRPV1 in vagal A‐fiber neurons may contribute to the heightened sensory sensitivity of individuals to various sensory irritants. Supported by NIH HL062296 & HL07534, Bethesda, MD