星形胶质细胞的兴奋对神经元树突丝运动的调节机制

神经元树突上树突丝(filopodia)的形成及其运动,是神经元探索胞外环境、寻找突触前膜结构的一种方式.为研究星形胶质细胞的兴奋对神经元树突上树突丝运动的调节机制,在与神经元混合培养的星形胶质细胞中转染光敏感通道(channelrhodopsin-2).Channelrhodopsin-2是一种可表达于细胞膜表面的非选择性阳离子通道,可被特定模式的蓝光激活,导致大量钙离子内流并进一步诱发星形胶质细胞产生钙波,从而实现了选择性激活星形胶质细胞的目的.研究结果显示,在混合培养的神经元与星形胶质细胞模型中,激活的星形胶质细胞可以抑制神经元filopodia的运动,与外源性ATP、谷氨酸的作用效果一致.这表明星形胶质细胞激活后可能通过释放ATP和谷氨酸等递质来抑制神经元filopodia的运动.

The effects of activity of astrocytes on neuron dendritic filopodia motility

The motile behavior of dendritic filopodia is a way by which neurons explore extracellular environment and could serve to connect dendrites with axons forming early synapses. It is unclear whether activity of astrocyte affects the motility of neuronal filopodia. To explore this possibility, astrocytes were transfected with channelrhodopsin-2 in a neuron-astrocyte mix culture model first. Expressing on cytoplasic membrane, channelrhodopsin-2 was activated by pulses of blue light and caused activation of astrocyte, in which different dynamic patterns of Ca²⁺ current were shown after the stimulation. Activated astrocytes have an inhibitory effect on filopodia motility similar to extracellularly administrated ATP and glutamate. This indicates that activated astrocytes could probably inhibit dendritic filopodia motility through releasing ATP or glutamate. A method of selectively activating astrocytes in the mix culture of neuron and astrocyte was established, which provides a novel way for studying astrocytic signal regulation of neuronal development.