Guo Zhi Y, Li Cheng Z, Li Xiao J, Wang Ya L, Mattson Mark P, Lu Cheng B
Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, People's Republic of China.
Neuroreport. 2013 Jun 19;24(9):492-7. doi: 10.1097/WNR.0b013e32836206b5.
We have studied the developmental changes of glutamate-induced calcium (Ca²⁺) response in primary cultured hippocampal neurons at three different stages of cultures, 3, 7-8, and 14-16 days in vitro (DIV), using fura-2 single-cell digital micro-fluorimetry. We found that glutamate-induced Ca²⁺ signaling was altered during development, and that two different ionotropic glutamate receptors, α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPARs) and N-methyl-D-aspartate receptors (NMDARs), were differently involved in the modulation of calcium response at different stages of neuronal culture. In the stages of culture at 3 and 8 DIV, glutamate-induced Ca²⁺ influx was mostly because of AMPAR activation and subsequent opening of voltage-dependent calcium channels, as Ca²⁺ response can be largely reduced by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and by nifedipine. In the advanced culture (14-17 DIV), glutamate-induced Ca²⁺ response was less sensitive to 6-cyano-7-nitroquinoxaline-2,3-dione and nifedipine. Furthermore, AMPA-induced Ca²⁺ response increased in a time-dependent manner during the cultures of 3-8 DIV and then reduced in the advanced culture of 14-17 DIV. NMDA-induced Ca²⁺ influx increased in a time-dependent manner, with a marked increase in the advanced culture (14-17 DIV). These results suggest that glutamate-induced Ca²⁺ signaling switched from AMPA-voltage-dependent calcium channel to NMDA-calcium signaling during development.
我们使用fura-2单细胞数字显微荧光测定法，研究了原代培养的海马神经元在体外培养的三个不同阶段（体外培养3天、7 - 8天和14 - 16天）中谷氨酸诱导的钙（Ca²⁺）反应的发育变化。我们发现，谷氨酸诱导的Ca²⁺信号在发育过程中发生了改变，并且两种不同的离子型谷氨酸受体，即α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体（AMPARs）和N-甲基-D-天冬氨酸受体（NMDARs），在神经元培养的不同阶段对钙反应的调节作用有所不同。在培养3天和8天的阶段，谷氨酸诱导的Ca²⁺内流主要是由于AMPAR激活以及随后电压依赖性钙通道的开放，因为Ca²⁺反应可被6-氰基-7-硝基喹喔啉-2,3-二酮（CNQX）和硝苯地平大大降低。在晚期培养阶段（14 - 17天体外培养），谷氨酸诱导的Ca²⁺反应对6-氰基-7-硝基喹喔啉-2,3-二酮和硝苯地平的敏感性较低。此外，在3 - 8天体外培养期间，AMPA诱导的Ca²⁺反应呈时间依赖性增加，然后在14 - 17天的晚期培养中降低。NMDA诱导的Ca²⁺内流呈时间依赖性增加，在晚期培养阶段（14 - 17天体外培养）有显著增加。这些结果表明，在发育过程中，谷氨酸诱导的Ca²⁺信号从AMPA-电压依赖性钙通道转换为NMDA-钙信号。
