缺氧对椭圆囊毛细胞谷氨酸递质合成及释放的影响.

Objective: To investigate the effects of hypoxia on the synthesis and release of glutamate acid in utricle hair cells in guinea pigs. Methods: Bilateral utricles of 4-week-old guinea pigs were isolated and treated in a constant oxygen (21% O2) and hypoxia (1% O2) condition for 30 minutes, respectively, in vitro. Western blotting and enzyme activity analysis were used to detect the activity and expression of glutaminase in hair cells and evaluate the change of synthesis of glutamate acid. The distributions of glutamate acid in utricles were detected by ELISA and immunofluorescence. Results: After exposed to hypoxia, the expression and activity of glutaminase, which are the key enzyme for synthesis of glutamate acid, did not change significantly. However, compared to the control group, ELISA results showed a 5.6% reduction of glutamate levels in hypoxia group (P<0.05), the results of immunofluorescence indicated that glutamate acid was more widely distributed in the basal area than area that close to kinocilium in cytoplasm of utricle hair cells in hypoxia group. Conclusion: Hypoxia treatment did not change the glutamate synthesis of hair cells, but increased the release of glutamate acid significantly in utricle hair cells in vitro. [ABSTRACT FROM AUTHOR]