哺乳动物大脑皮层锥体神经元顶树突电兴奋性问题  

Electrical excitability of the apical dendrites of mammalian cortical pyramidal neurons

作　　者：范世藩[1] 

机构地区：[1]原中国科学院上海生理研究所,上海200031

出　　处：《生理学报》2012年第6期707-712,共6页Acta Physiologica Sinica

摘　　要：对树突电兴奋性的研究始于大脑皮层锥体神经元的顶树突。20世纪50年代张香桐在这方面做出了重要贡献。现在已经清楚,不同神经元的树突,甚至是同一神经元不同树突的电兴奋性是不同的。在大脑皮层锥体神经元顶树突,源自细胞体的单个或频率恒定的重复动作电位都不能上溯到顶树突的末端部分。可是由直流电注入细胞体引起的爆发型、频率不恒定的重复放电中,有些动作电位却可以上溯到顶树突的末端部分。其原因可能有二:(1)顶树突内的钙离子浓度增加,提高了树突的电兴奋性;(2)被激活了的细胞体轴突的侧枝在树突末端部分释放的谷氨酸改变了那里电压控制的离子通道的性质。顶树突的电兴奋性较低,应该是顶树突处理大量输入信号所必须。The electrical excitability of the dendrites of the cortical neurons was first studied on the apical dendrites of the pyramidal neurons. Professor ZHANG Xiang-Tong （H-T Chang） made important contributions in the fifties of last century on this topic. Through numerous studies later on, it has been established that the electrical excitability of dendrites of different types of neurons, even different dendrites in the same neuron is different. For the apical dendrites of the cortical pyramidal neurons, neither a single nor a train of repetitive action potentials with constant frequency can reach its terminal portion. However, some of the burst repetitive responses with non-constant frequency of the apical dendrite elicited by direct current injected into the soma may reach the terminal portion. This may be due to： （1） the calcium ion concentration in the apical dendrite is increased by the burst activities, which, in turn, increases the electrical excitability of the apical dendrite and /or （2） some retrograde collaterals of axon of the activated soma reach the apical dendrite and release neurotransmitter glutamate, which changes the properties of the voltage-gated ion channels in the apical dendrite. Low electrical excitability of the apical dendrites seems to be essential for the processing of numerous income signals to the terminal portion of the apical dendrites.

关 键 词：张香桐 顶树突 电性质 

分 类 号：Q42[生物学—神经生物学]