title: Immunohistochemical localization of histamine N-methyltransferase in guinea pig tissues.
abstract: Histamine plays important roles in gastric acid secretion, inflammation, and allergic response. Histamine N-methyltransferase (HMT; EC 2.1.1.8) is crucial to the inactivation of histamine in tissues. In this study we investigated the immunohistochemical localization of this enzyme in guinea pig tissues using a rabbit polyclonal antibody against bovine HMT. The specificity of the antibody for guinea pig HMT was confirmed by Western blotting and the lack of any staining using antiserum preabsorbed with purified HMT. There was strong HMT-like immunoreactivity (HMT-LI) in the epithelial cells in the gastrointestinal tract, especially in the gastric body, duodenum, and jejunum. The columnar epithelium in the gallbladder was also strongly positive. Almost all the myenteric plexus from the stomach to the colon was stained whereas the submucous plexus was not. Other strongly immunoreactive cells included the ciliated cells in the trachea and the transitional epithelium of the bladder. Intermediately immunoreactive cells included islets of Langerhans, epidermal cells of the skin, alveolar cells in the lung, urinary tubules in the kidney, and epithelium of semiferous tubules. HMT-LI was present in specific structures in the guinea pig tissues. The widespread distribution of HMT-LI suggests that histamine has several roles in different tissues.
authors.affiliation: Department of Pharmacology, Okayama University Medical School, Okayama, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Tahara
authors.forename: M
authors.initials: M
authors.lastname: Nishibori
authors.forename: A
authors.initials: A
authors.lastname: Ohtsuka
authors.forename: K
authors.initials: K
authors.lastname: Sawada
authors.forename: J
authors.initials: J
authors.lastname: Sakiyama
authors.forename: K
authors.initials: K
authors.lastname: Saeki
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D002417:Cattle; D004064:Digestive System / Q000201:enzymology; D006168:Guinea Pigs; D006637:Histamine N-Methyltransferase / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D009928:Organ Specificity; D011817:Rabbits; D012137:Respiratory System / Q000201:enzymology; D014566:Urogenital System / Q000201:enzymology
chemical_list: D006637:Histamine N-Methyltransferase