Sustained neuronal activity generated by glial plasticity.
Sustained neuronal activity generated by glial plasticity.
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DOI：
10.1523/jneurosci.5783-10.2011
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发表时间：
2011-05-25
期刊：
影响因子：
--
通讯作者：
Parri HR
中科院分区：
文献类型：
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作者：
Pirttimaki TM;Hall SD;Parri HR
星形胶质细胞释放神经胶质递质，特别是谷氨酸，可以影响神经元和突触的活动。特别是，星形细胞谷氨酸的释放导致神经元产生N-甲基-D-天冬氨酸受体(NMDA-R)介导的慢内向电流(SIC)。然而，SICS出现的潜在因素及其生理作用在很大程度上是未知的。在这里，我们发现，在大鼠体感觉丘脑的急性脑片中，刺激丘脑或皮质传入导致丘脑皮质(TC)神经元SIC的持续增加，这种增加持续时间超过刺激持续一个小时。星形胶质细胞谷氨酸释放的这种长期增强(LTE)是由I组代谢性谷氨酸受体(MGluRs)诱导的，并依赖于星形胶质细胞内钙([Ca~(2+)]i)。神经元SICs是由突触外含NR2B亚单位的NMDA-R介导的，能够诱发猝发。这些不同于T型钙通道依赖的动作电位爆发，并且在相邻的TC神经元中是同步的。这些发现描述了中枢神经系统(CNS)中一种以前未被认识到的兴奋性、非突触可塑性，这种可塑性在刺激终止很长时间后向前馈送，产生局部神经元放电。
Astrocytes release gliotransmitters, notably glutamate, that can affect neuronal and synaptic activity. In particular, astrocytic glutamate release results in the generation of N-methyl D-aspartate receptor (NMDA-R) mediated slow inward currents (SICs) in neurons. However, factors underlying the emergence of SICs, and their physiological roles are largely unknown. Here we show that, in acute slices of rat somatosensory thalamus, stimulation of Lemniscal or cortical afferents results in a sustained increase of SICs in thalamocortical (TC) neurons that outlasts the duration of the stimulus by an hour. This long term enhancement (LTE) of astrocytic glutamate release is induced by group I metabotropic glutamate receptors (mGluRs), and is dependent on astrocytic intracellular calcium ([Ca2+]i). Neuronal SICs are mediated by extrasynaptic NR2B subunit-containing NMDA-Rs and are capable of eliciting bursts. These are distinct from T-type Ca2+ channel dependent bursts of action potentials, and are synchronized in neighboring TC neurons. These findings describe a previously unrecognized form of excitatory, non-synaptic plasticity in the central nervous system (CNS) that feeds forward to generate local neuronal firing long after stimulus termination.