Characteristic expression of gamma-aminobutyric acid and glutamate decarboxylase in rat jejunum and its relation to differentiation of epithelial cells.
OBJECTIVE
To investigate the expression between gamma-aminobutyric acid (GABA) and glutamate decarboxylase and its relation with differentiation and maturation of jejunal epithelial cells in rat jejunum.


METHODS
Immunohistochemical expression of GABA and glutamate decarboxylase (GAD, including two isoforms, GAD65 and GAD67) was investigated in rat jejunum. Meanwhile, double staining was performed with GAD65 immunohistochemistry, followed by lectin histochemistry of fluorescent wheat germ agglutinin. Furthermore, evaluation of cell kinetics in jejunum was conducted by (3)H-thymidine autoradiography and immunohistochemistry using a monoclonal antibody to proliferating cell nuclear antigen (PCNA).


RESULTS
The cells showing positive immunoreactivity GABA and GAD65 were mainly distributed in the villi in rat jejunum, while jejunal epithelial cells were negative for GAD67. Positive GABA or GAD65 staining was mainly located in the cytoplasm and along the brush border of epithelial cells in the middle and upper portions. In addition, a few GABA and GAD65 strongly positive cells were scattered in the upper two thirds of jejunal villi. Double staining showed that GAD65 immunoreactivity was not found in goblet cells. (3)H-thymidine-labeled nuclei were found in the lower and middle portions of jejunal crypts, which was consistent with PCNA staining. Therefore, GABA and GAD65 were expressed in a maturation or functional zone.


CONCLUSIONS
The characteristic expression of GABA and GAD suggests that GABA might be involved in regulation of differentiation and maturation of epithelial cells in rat jejunum.
Wang
Fang-Yu
FY
Department of Gastroenterology, Nanjing General Hospital of Nanjing Military Command, Nanjing 210002, Jiangsu Province, China. wangf65@yahoo.com
Watanabe
Masahito
M
Zhu
Ren-Min
RM
Maemura
Kentaro
K
D000818:Animals; D001345:Autoradiography; D002454:Cell Differentiation / Q000502:physiology; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology; D005968:Glutamate Decarboxylase / Q000378:metabolism*; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000166:cytology / Q000201:enzymology; D007583:Jejunum / Q000166:cytology* / Q000201:enzymology*; D008297:Male; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013936:Thymidine / Q000493:pharmacokinetics; D014316:Tritium; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D018809:Proliferating Cell Nuclear Antigen; D014316:Tritium; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; D013936:Thymidine