title: Role of prostaglandin D2 in mast cell activation-induced sensitization of esophageal vagal afferents.
abstract: Sensitization of esophageal afferents plays an important role in esophageal nociception, but the mechanism is less clear. Our previous studies demonstrated that mast cell (MC) activation releases the preformed mediators histamine and tryptase, which play important roles in sensitization of esophageal vagal nociceptive C fibers. PGD2 is a lipid mediator released by activated MCs. Whether PGD2 plays a role in this sensitization process has yet to be determined. Expression of the PGD2 DP1 and DP2 receptors in nodose ganglion neurons was determined by immunofluorescence staining, Western blotting, and RT-PCR. Extracellular recordings were performed in ex vivo esophageal-vagal preparations. Action potentials evoked by esophageal distension were compared before and after perfusion of PGD2, DP1 and DP2 receptor agonists, and MC activation, with or without pretreatment with antagonists. The effect of PGD2 on 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled esophageal nodose neurons was determined by patch-clamp recording. Our results demonstrate that DP1 and DP2 receptor mRNA and protein were expressed mainly in small- and medium-diameter neurons in nodose ganglia. PGD2 significantly increased esophageal distension-evoked action potential discharges in esophageal nodose C fibers. The DP1 receptor agonist BW 245C mimicked this effect. PGD2 directly sensitized DiI-labeled esophageal nodose neurons by decreasing the action potential threshold. Pretreatment with the DP1 receptor antagonist BW A868C significantly inhibited PGD2 perfusion- or MC activation-induced increases in esophageal distension-evoked action potential discharges in esophageal nodose C fibers. In conclusion, PGD2 plays an important role in MC activation-induced sensitization of esophageal nodose C fibers. This adds a novel mechanism of visceral afferent sensitization.
authors.affiliation: Division of Gastroenterology, Dept. of Medicine, Univ. of Michigan Medical School, Ann Arbor, MI 48105, USA.
authors.forename: Shizhong
authors.initials: S
authors.lastname: Zhang
authors.forename: Gintautas
authors.initials: G
authors.lastname: Grabauskas
authors.forename: Xiaoyin
authors.initials: X
authors.lastname: Wu
authors.forename: Moon Kyung
authors.initials: MK
authors.lastname: Joo
authors.forename: Andrea
authors.initials: A
authors.lastname: Heldsinger
authors.forename: Il
authors.initials: I
authors.lastname: Song
authors.forename: Chung
authors.initials: C
authors.lastname: Owyang
authors.forename: Shaoyong
authors.initials: S
authors.lastname: Yu
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D015153:Blotting, Western; D002232:Carbocyanines; D003627:Data Interpretation, Statistical; D004947:Esophagus / Q000187:drug effects / Q000294:innervation*; D005455:Fluorescent Antibody Technique; D006168:Guinea Pigs; D008297:Male; D008407:Mast Cells / Q000187:drug effects*; D009412:Nerve Fibers / Q000502:physiology; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects; D009475:Neurons, Afferent / Q000187:drug effects*; D009620:Nodose Ganglion / Q000166:cytology / Q000187:drug effects; D018408:Patch-Clamp Techniques; D010812:Physical Stimulation; D015230:Prostaglandin D2 / Q000378:metabolism / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D011971:Receptors, Immunologic / Q000819:agonists / Q000187:drug effects; D011982:Receptors, Prostaglandin / Q000819:agonists / Q000187:drug effects; D014630:Vagus Nerve / Q000187:drug effects*
chemical_list: D002232:Carbocyanines; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; C024286:3,3'-dioctadecylindocarbocyanine; D015230:Prostaglandin D2; C036293:prostaglandin D2 receptor
keywords: C fiber; PGD2; esophagus; mast cell; vagal afferent