Two major types of nociceptors have been described in dorsal root ganglia (DRGs). In comparison, little is known about the vagal nociceptor subtypes. The vagus nerves provide much of the capsaicin-sensitive nociceptive innervation to visceral tissues, and are likely to contribute to the overall pathophysiology of visceral inflammatory diseases. The cell bodies of these afferent nerves are located in the vagal sensory ganglia referred to as nodose and jugular ganglia. Neurons of the nodose ganglion are derived from the epibranchial placodes, whereas jugular ganglion neurons are derived from the neural crest. In the adult mouse, however, there is often only a single ganglionic structure situated alone in the vagus nerve. By employing Wnt1Cre/R26R mice, which express β-galactosidase only in neural crest derived neurons, we found that this single vagal sensory ganglion is a fused ganglion consisting of both neural crest neurons in the rostral portion and non-neural crest (nodose) neurons in the more central and caudal portions of the structure. Based on their activation and gene expression profiles, we identified two major vagal capsaicin-sensitive nociceptor phenotypes, which innervated a defined target, namely the lung in adult mice. One subtype is non-peptidergic, placodal in origin, expresses P2X2 and P2X3 receptors, responds to α,β-methylene ATP, and expresses TRKB, GFRα1 and RET. The other phenotype is derived from the cranial neural crest and does not express P2X2 receptors and fails to respond to α,β-methylene ATP. This population can be further subdivided into two phenotypes, a peptidergic TRKA + and GFRα3 + subpopulation, and a non-peptidergic TRKB + and GFRα1 + subpopulation. Consistent with their similar embryonic origin, the TRPV1 expressing neurons in the rostral dorsal root ganglia were more similar to jugular than nodose vagal neurons. The data support the hypothesis that vagal nociceptors innervating visceral tissues comprise at least two major subtypes. Due to distinctions in their gene expression profile, each type will respond to noxious or inflammatory conditions in their own unique manner.

Transient Receptor Potential A1 (TRPA1) is a nonselective cation channel, preferentially expressed on a subset of nociceptive sensory neurons, that is activated by a variety of reactive irritants via the covalent modification of cysteine residues. Excessive nitric oxide during inflammation (nitrative stress), leads to the nitration of phospholipids, resulting in the formation of highly reactive cysteine modifying agents, such as nitrooleic acid (9-OA-NO 2 ). Using calcium imaging and electrophysiology, we have shown that 9-OA-NO 2 activates human TRPA1 channels (EC 50 , 1 M), whereas oleic acid had no effect on TRPA1. 9-OA-NO 2 failed to activate TRPA1 in which the cysteines at positions 619, 639, and 663 and the lysine at 708 had been mutated. TRPA1 activation by 9-OA-NO 2 was not inhibited by the NO scavenger carboxy-PTIO. 9-OA-NO 2 had no effect on another nociceptive-specific ion channel, TRPV1. 9-OA-NO 2 activated a subset of mouse vagal and trigeminal sensory neurons, which also responded to the TRPA1 agonist allyl isothiocyanate and the TRPV1 agonist capsaicin. 9-OA-NO 2 failed to activate neurons derived from TRPA1(Ϫ/Ϫ) mice. The action of 9-OA-NO 2 at nociceptive nerve terminals was investigated using an ex vivo extracellular recording preparation of individual bronchopulmonary C fibers in the mouse. 9-OA-NO 2 evoked robust action potential discharge from capsaicin-sensitive fibers with slow conduction velocities (0.4 -0.7 m/s), which was inhibited by the TRPA1 antagonist AP-18. These data demonstrate that nitrooleic acid, a product of nitrative stress, can induce substantial nociceptive nerve activation through the selective and direct activation of TRPA1 channels.Oxidative stress and nitrative stress have been implicated as contributing to acute and chronic inflammation (Radi, 2004;Szabó et al., 2007;Valko et al., 2007). Nitric oxide (NO) is an endogenous mediator with multiple cellular functions that is produced by many cell types including vascular endothelium, neutrophils, fibroblasts, and nerves (Bian and Murad, 2003). NO, generated from L-arginine by NO synthases (NOS), reacts with the reactive oxygen species (ROS) superoxide-which is formed through multiple pathways in inflammation, including NADPH oxidase, xanthine oxidase, and perverted mitochondrial function-to produce the reactive nitrogen species (RNS), peroxynitrite (ONOOϪ), and nitrogen dioxide (*NO 2 ). RNS are potent inflammatory molecules that can react with lipids, proteins, and DNA (Szabó et al., 2007). Within membranes, where the hydrophobic environment maximizes RNS production (Möller et al., 2007), RNS react with unsaturated fatty acids (e.g., oleic acid), causing the addition of an NO 2 group (nitration) Jain et al., 2008;Trostchansky and Rubbo, 2008). Nitrated fatty acids (e.g., nitrooleic acid) are highly reactive electrophilic compounds that can modulate a variety of cellular targets, including thiol residues and peroxisome proliferator-activated receptor ␥ Trostchansky and Rubbo, 2008 ABBREVIATIONS: NOS, nitric-oxide ...

Diverted dysplasia occurred infrequently with rates overlapping those reported in registries for IBD-based rectal cancers. Neoplasia was undetected in patients with < 10 pyd, regardless of diversion duration, suggesting low yield for endoscopic surveillance before this time.

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