鸡胚脑细胞谷氨酸释放的模拟微重力效应

用回转器旋转鸡胚蛋研究对脑细胞的模拟微重力生物效应.采用连续荧光法测量孵化10 d（E10）和孵化13 d（E13）鸡胚的脑细胞谷氨酸的初始释放速率、在KCl去极化及单个电脉冲刺激后的释放速率和释放量以及谷氨酸的含量，并对旋转处理组和静止对照组进行了比较.结果如下：旋转组和对照组脑细胞的谷氨酸初始释放速率没有显著差异，E10鸡胚经24 h旋转后，在KCl刺激下脑细胞的谷氨酸释放速率和释放量皆高于对照组，经4 h旋转后谷氨酸含量显著增高（P＜0.01）；但旋转24 h的E13鸡胚上述指标皆无显著改变，表明微重力对鸡胚脑细胞神经递质释放的影响与胚龄有关.鸡胚脑细胞在电脉冲刺激下谷氨酸释放的动态过程表明：脉冲电场引起的谷氨酸释放与细胞内钙离子迅速增加有关.

Simulated Biological Effects of Microgravity on Glutamate Release from Brain Cells of Embryonic Chicks

Biological effects of microgravity on brain cells were simulated by rotating chicken embryos in a clinostat during their hatch. Continuous fluorometry was used to study dynamic release of glutamate from brain cells of the embryonic chicks. The initial release rate, the induced release rate, the release content by KCl or by a single electric pulse and the total intracellular glutamate concentration have been compared between rotated and control groups. The results showed that there was no obvious difference in initial release rate between both rotated and controls. The total intracellular glutamate concentration increased significantly (P<0.01) when E10 embryos were rotated for 4 h, and KCl- induced release rate and release content from brain cells of E10 embryos rotated for 24 h were higher than those from controls. However, there was no significant difference in the total intracellular glutamate concentration and the KCl- induced release rate, release content from brain cells of E13 embryos between rotated and their control groups. These results suggest that the releasing behaviors of neuro-transmitters from brain cells can be affected by microgravity and the influence is related to the age of the embryos. The dynamic process of glutamate release from brain cells induced by a singlee electric pulse shows that the release is related with a rapid increase of the intracellular i following the pulse.