Immunocytochemical localization of monoamine oxidase type B in enterochromaffin-like cells of rat oxyntic mucosa.
We used immunohistochemistry to identify the localization of monoamine oxidase type B (MAOB) in the rat oxyntic mucosa. At light microscopic levels, MAOB-immunopositive cells were mostly located in the basal half of the oxyntic mucosa. By a double-labeling immunofluorescence method, it was shown that MAOB immunoreactivity was localized in almost all of histidine decarboxylase (HDC)-positive cells. Only a few MAOB-positive cells were negative for HDC. At electron microscopic levels, immunohistochemical reaction products of MAOB were detected on the mitochondrial outer membranes in cells that showed morphological characteristics of enterochromaffin-like (ECL) cells. These findings indicate that ECL cells contain MAOB in the rat. We provide a hypothesis that MAOB is involved in the inactivation mechanism of histamine that is released from ECL cells and activates parietal cells to secrete gastric acid.
Okauchi
H
H
Department of Surgery, Shiga University of Medical Science, Seta, Tsukinowa-cho, Otsu, 520-2192, Shiga, Japan.
Nakajima
S
S
Tani
T
T
Ito
A
A
Arai
R
R
D000818:Animals; D019861:Enterochromaffin-like Cells / Q000201:enzymology*; D005753:Gastric Mucosa / Q000201:enzymology*; D006640:Histidine Decarboxylase / Q000378:metabolism*; D008297:Male; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism*; D008995:Monoamine Oxidase / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley
D008995:Monoamine Oxidase; D006640:Histidine Decarboxylase