ABSTRACT
Histamine is an important mediator of many physiological processes including gastrointestinal function that acts via four different histamine receptors (H1R to H4R). Elevated histamine levels and increased HR messenger ribonucleic acid (mRNA) have been shown in humans with gastrointestinal disorders such as irritable bowel syndrome or allergic intestinal diseases. As there is limited knowledge concerning the distribution of histamine receptors (HR) in dogs, one aim of this study was to investigate the expression of histamine 1 receptor (H1R), histamine 2 receptor (H2R) and histamine 4 receptor (H4R) in the canine gastrointestinal tract at protein level using immunohistochemistry. Histamine 1 receptor, H2R and H4R were widely expressed throughout the canine gastrointestinal tract including epithelial, mesenchymal, neuronal and immune cells. In addition, in situ hybridisation was established for detecting canine H4R mRNA. Results showed H4R mRNA to be present in enterocytes, lamina propria immune cells and submucosal plexus in the duodenum and colon of nearly all investigated animals. The results elucidate the importance of HR in the canine gut and represent the basis for investigating their possible impact on canine inflammatory gastrointestinal disorders.
Subject(s)
Dogs , Gastrointestinal Tract/metabolism , Receptors, Histamine H1/biosynthesis , Receptors, Histamine H2/biosynthesis , Animals , Epithelial Cells/metabolism , Female , Gastrointestinal Diseases/pathology , Male , Mesoderm/metabolism , Mucous Membrane/metabolism , RNA, Messenger/genetics , Receptors, Histamine H1/genetics , Receptors, Histamine H2/geneticsABSTRACT
A cutaneous mass in the neck was excised in a 13-year-old cat. Histopathological examination of the resected tissue revealed a multicentric squamous cell carcinoma in situ resembling Bowen's disease of man. The tumor showed a multifocal transformation to an infiltrative squamous cell carcinoma. Histological and immunohistological findings excluded actinic keratosis and feline viral plaques and allowed a classification as an irregular non-hyperkeratotic type of multicentric squamous cell carcinoma in situ. As a possible causative agent feline papillomavirus type 2 was detected using nested PCR in formalin-fixed material.
