title: Cellular localization of monoamine oxidase A and B in human tissues outside of the central nervous system.
abstract: We studied the localization of monoamine oxidase (MAO) A and B in human heart, liver, duodenum, blood vessels and kidney by immunohistochemistry. The primary antibodies used were mouse monoclonal anti-human MAO-A (6G11/E1) and anti-human MAO-B (3F12/G10/2E3). Samples were obtained from six routine autopsy cases and fixed in 2% paraformaldehyde. All cardiomyocytes and hepatocytes showed MAO-A and MAO-B immunoreactivity. In the duodenum, both immunoreactivities were present in all cells of the villi, Lieberkühn crypts, muscularis mucosae and muscular layers, whereas Brunner glands were devoid of MAO-A and MAO-B staining. Endothelial cells of lymphatic vessels showed MAO-A but no MAO-B immunoreactivity, whereas arteries and veins presented MAO-A and MAO-B staining in muscular layers and fibroblasts but not in endothelial cells. In the kidney, renal tubuli showed MAO-A and MAO-B immunoreactivities, whereas collecting ducts and the Bowman's capsule showed only MAO-A staining. These data represent the first study of the cellular distribution of MAO-A and MAO-B in these human tissues. They show that both enzymes have a widespread distribution in the human body with a matching pattern in many, but not all tissues, and with strong differences from the pattern of distribution in rodents.
authors.affiliation: Unitat de Bioquímica, Institut d'Investigacions Biomédiques August Pi i Sunye, Facultat de Medicina, Universitat de Barcelona, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Rodríguez
authors.forename: J
authors.initials: J
authors.lastname: Saura
authors.forename: E E
authors.initials: EE
authors.lastname: Billett
authors.forename: C C
authors.initials: CC
authors.lastname: Finch
authors.forename: N
authors.initials: N
authors.lastname: Mahy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000918:Antibody Specificity; D001808:Blood Vessels / Q000166:cytology / Q000201:enzymology; D004386:Duodenum / Q000166:cytology / Q000201:enzymology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000166:cytology / Q000201:enzymology; D008099:Liver / Q000166:cytology / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000032:analysis* / Q000276:immunology; D009206:Myocardium / Q000166:cytology / Q000201:enzymology; D014018:Tissue Distribution
chemical_list: D008995:Monoamine Oxidase