ABSTRACT
Objevtives: To explore the relationship between ? aminobutyric acid (GABA) and the proliferation or differentiation of jejunal epithelial cells. Methods: Immunohistochemical expression of GABA, 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, cell kinetics was evaluated by immunohistochemistry using a monoclonal antibody to proliferating cell nuclear antigen (PCNA). Results: Immunoreactive GABA and GAD65 were distributed in the villi of jejunum, while GAD67 was negative in epithelial cells. Strong positive staining of GABA and GAD65 was mainly localized along the brush border of jejunal villi. In addition, there existed a few GABA and GAD65 strong positive cells scattering in upper portion of the jejunal villi. Double staining showed that immunoreactive GAD65 was not found in goblet cells. PCNA staining nucleoli were found in the lower and the middle portions of the jejunal crypts. Therefore, GABA and GAD65 were expressed in maturation or functional zone. Conclusion: It suggests that GABA might be involved in the regulation of differentiation and maturation of epithelial cells in rat jejunum.