新鲜分离的新生大鼠皮层神经元的钙振荡

目的:研究新鲜分离的新生大鼠皮层神经元胞内钙离子浓度(Ca~(2 )]_i)发生振荡的机制。方法:采用酶解结合机械分离法从6—7日龄大鼠分离皮层神经元,用M40钙离子测量系统(PTI)测量细胞内钙离子浓度的变化。用Fura-2作为钙离子指示剂。结果:在观察到的82个神经元细胞中,47个产生了自发钙振荡。自发钙振荡依赖于胞外钙离子浓度。去除外钙后自发钙振荡立即停止。四乙铵1mmol/L引起钙振荡振幅增大,频率变快。CsCl 1mmol/L主要引起频率增加。BaCl_2 1mmol/L可使振幅、频率增高,并有明显的高台样基线增加。结论:皮层神经元在无突触联系的情况下具有产生自发Ca~(2 )]_i振荡的特性,K~ 通道在决定钙振荡的幅值和频率方面起重要作用。

Calcium oscillations in freshly isolated neonatal rat cortical neurons

AIM: To investigate the mechanisms of intracellular calcium concentration (Ca2 ]i) oscillations in freshly isolated neonatal rat cortical neurons. METHODS: Cortical neurons were isolated from neonatal rats 6-7 d after birth by enzymatic digestion. Ca2 ]i changes were measured in a microscopic calcium measurement system with Fura-2 as indicator. RESULTS: In a total of 82 neurons recorded, 47 showed spontaneous Ca2 ]i oscillations. The spontaneous Ca2 ]i oscillations were dependent on Ca2 ]0. Removal of Ca2 ]0 complete-ly abolished spontaneous oscillations. Tetraethylammo-nium 1 mmol/L increased both the amplitude and frequency of calcium oscillations, whereas the frequency was increased by Cs 1 mmol/L. Ba2 1 mmol/L, in contrast, induced Ca2 ]i oscillations superimposed on a sustained phasic increase. CONCLUSION: Sponta-neous Ca2 ]i oscillation is an intrinsic property of neonatal rat cortical neurons. Potassium channels play an important role in the control of both the amplitude and frequency of Ca2 ]i oscillations in cortical neurons.