title: House-dust mite allergen and ozone exposure decreases histamine H3 receptors in the brainstem respiratory nuclei.
abstract: Allergic airway diseases in children are a common and a growing health problem. Changes in the central nervous system (CNS) have been implicated in contributing to some of the symptoms. We hypothesized that airway allergic diseases are associated with altered histamine H3 receptor expression in the nucleus tractus solitarius (NTS) and caudal spinal trigeminal nucleus, where lung/airway and nasal sensory afferents terminate, respectively. Immunohistochemistry for histamine H3 receptors was performed on brainstem sections containing the NTS and the caudal spinal trigeminal nucleus from 6- and 12-month-old rhesus monkeys who had been exposed for 5 months to house dust mite allergen (HDMA)+O3 or to filtered air (FA). While histamine H3 receptors were found exclusively in astrocytes in the caudal spinal trigeminal nucleus, they were localized to both neuronal terminals and processes in the NTS. HDMA+O3 exposure significantly decreased histamine H3 receptor immunoreactivity in the NTS at 6 months and in the caudal spinal trigeminal nucleus at 12 months of age. In conclusion, exposing young primates to HDMA+O3 changed histamine H3 receptor expression in CNS pathways involving lung and nasal afferent nerves in an age-related manner. Histamine H3 receptors may be a therapeutic target for allergic asthma and rhinitis in children.
authors.affiliation: Department of Pharmacology, School of Medicine, University of California Davis, GBSF Rm. 3617, 451 Health Sciences Drive, Davis, CA 95616-0635, USA. ssekizawa@ucdavis.edu
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Sekizawa
authors.forename: Andrea G
authors.initials: AG
authors.lastname: Bechtold
authors.forename: Rick C
authors.initials: RC
authors.lastname: Tham
authors.forename: Kayleen S
authors.initials: KS
authors.lastname: Kott
authors.forename: Dallas M
authors.initials: DM
authors.lastname: Hyde
authors.forename: Jesse P
authors.initials: JP
authors.lastname: Joad
authors.forename: Ann C
authors.initials: AC
authors.lastname: Bonham
mesh_terms: D000375:Aging / Q000276:immunology / Q000378:metabolism; D000818:Animals; D004195:Disease Models, Animal; D019570:Inhalation Exposure / Q000009:adverse effects*; D008253:Macaca mulatta; D010126:Ozone / Q000633:toxicity*; D039981:Pyroglyphidae / Q000276:immunology*; D018100:Receptors, Histamine H3 / Q000032:analysis / Q000096:biosynthesis*; D012130:Respiratory Hypersensitivity / Q000276:immunology* / Q000378:metabolism; D017552:Solitary Nucleus / Q000187:drug effects* / Q000254:growth & development / Q000276:immunology / Q000378:metabolism; D014279:Trigeminal Nucleus, Spinal / Q000187:drug effects / Q000254:growth & development / Q000276:immunology / Q000378:metabolism
chemical_list: D018100:Receptors, Histamine H3; D010126:Ozone