title: Neural pathways involved in food allergy signaling in the mouse brain: role of capsaicin-sensitive afferents.
abstract: There is increasing evidence supporting the notion that brain-gut communication is crucial for the manifestation of functional gastrointestinal (GI) disorders. Employing denervation by neonatal capsaicin treatment, we investigated here the role of unmyelinated C-fibers in food allergy signaling in the brain. We found that 90 min after oral ovalbumin (OVA) challenge, allergic mice present increased c-fos expression in emotionality-related brain areas such as the paraventricular nucleus of the hypothalamus (PVN) and the central nucleus of the amygdala (CeA). Food allergy also induced enhanced Fos immunoreactivity in the nucleus of tractus solitarii (NTS) of OVA-immunized animals. We also show that while the degree of Fos staining in the NTS of allergic mice was only diminished by neonatal capsaicin, it was completely blocked in the PVN. However, capsaicin did not modify food allergy-induced c-fos expression in the CeA. In conclusion, this study provides evidence showing that unmyelinated C-fibers are part of the neural pathways involved in food allergy-induced activation of specific brain areas, particularly the PVN and to a lesser extent the NTS.
authors.affiliation: Department of Pathology, School of Veterinary Medicine, University of São Paulo, Av. Orlando Marques de Paiva, 87 São Paulo, SP 05508-900, Brazil.
authors.forename: Alexandre Salgado
authors.initials: AS
authors.lastname: Basso
authors.forename: Frederico Azevedo
authors.initials: FA
authors.lastname: Costa-Pinto
authors.forename: Luiz Roberto Giorgetti
authors.initials: LR
authors.lastname: Britto
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: de Sá-Rocha
authors.forename: João
authors.initials: J
authors.lastname: Palermo-Neto
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002211:Capsaicin / Q000494:pharmacology; D002452:Cell Count / Q000379:methods; D005512:Food Hypersensitivity / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D005786:Gene Expression Regulation; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology*; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D010047:Ovalbumin / Q000009:adverse effects / Q000276:immunology; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D017552:Solitary Nucleus / Q000187:drug effects / Q000378:metabolism*
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D010047:Ovalbumin; D002211:Capsaicin