红藻氨酸对大鼠海马锥体细胞钙电流的影响

目的：应用膜片钳技术，观察红藻氨酸（KA）对大鼠海马锥体细胞ca2＋电流的影响，以研究癫痫的发病机制。方法：采用酶加机械分离法制备出生10～12d的大鼠海马锥体神经元标本，用全细胞膜片钳技术测定其生理学特性及观察KA对ca2＋电流的影响。结果：分离出的海马锥体细胞形态正常，有较长突起；用膜片钳技术证实，其保存了主要的离子通道活性。KA20μmol／L和100μmol／L的浓度均可使海马锥体细胞ca2＋电流峰值增大（n=8，P〈0．01）。结论：①大鼠海马锥体神经细胞具有明显的突起，细胞膜表面光洁、晕光好，适用于膜片钳实验研究；②KA使ca2＋内流增加，引起“Ca”超载”导致细胞毒性等一系列反应；③KA通过激活α-氨基羟甲基恶唑丙酸（AMPA）受体，诱发快速的兴奋性突触后电位（EPSP），参与兴奋性突触传递。AMPA受体的激活可能是癫痫的发病机制之一。

The effect of kainic acid on calcium currents in hippocampal pyramidal neurons of rat

Objective：To examine the effect of kainie acid（KA） on Ca2＋ currents in freshly dissoci- ated hippocampal pyramidal neurons, and to investigate the mechanism of epilepsy. Methods： The hippocampal pyramidal neurons were obtained with the combination of mechanical and enzymatic means from 10- 12 day-old rats. Whole-cell patch clamp technique was used to measure the electrophysiological properties of the neurons and to investigate the effect of KA. Results：The isolated neurons had regular configuration with long neuraxons. With patch-clamp techniques the activities of primary iron channels were protected. Upon the administration of KA 20,100 μmol/L, the current of Ca2＋ was significantly increased （n = 8, P〈0.01 ）. Conclusion： The hippocampal pyramidal neurons have long neuraxons, with clean surface. KA induces a series of responses such as cytotoxin in nlrich ＂calcium overload＇increased and is induced in Ca2＋ influ.