Synchronization without active chemical synapses during hippocampal afterdischarges.
Synchronization without active chemical synapses during hippocampal afterdischarges.
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DOI：
10.1152/jn.1984.52.1.143
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发表时间：
1984-07
影响因子：
2.5
通讯作者：
Charles P. Taylor;F. Dudek
中科院分区：
文献类型：
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作者：
Charles P. Taylor;F. Dudek
在大鼠海马横片上观察了逆行刺激引起的后放电。将切片在含有Mn 2+的静态浴培养基中孵育，其中Ca 2+浓度降低，其阻断化学突触传递。从微量移液器的细胞外电压记录揭示了群体尖峰的后放电，这代表了同步动作电位。后放电持续时间随孵育时间的延长而延长，有时可达9s。同时记录从三个细胞外微量移液器表明传播的个别人口尖峰沿着CA 1细胞体层在afterdischarge。从锥体细胞的细胞内记录表明，动作电位与群体尖峰同步。当初始动作电位的后放电被超极化刺穿的细胞，随后的动作电位保持同步与人口尖峰，表明神经元之间的同步相互作用。体内神经元记录有时也显示部分动作电位，也与人口尖峰同步。在后放电过程中，相对较弱（10 mV）的超极化阻断全部和部分动作电位。这些观察结果表明，同步动作电位和部分尖峰附近的索马启动。细胞内电压记录参考局部细胞外微电极，以便在存在大群体尖峰的情况下更准确地确定跨膜电位。这样的神经元记录揭示了短暂的跨膜去极化，与人口尖峰同步发生。大的注入超极化电流不影响短暂的跨膜去极化。类似的跨神经胶质细胞膜的差分电压记录没有显示出可测量的短暂的跨膜去极化在人口尖峰。然而，缓慢的胶质细胞去极化后放电过程中表示延长K+积累和清除的细胞外空间，这可能有助于过度兴奋的锥体细胞。在后放电过程中，细胞外电位同时记录从六个微量移液管垂直排列的皮层。电流源密度分析表明，在细胞体层中的汇在人口尖峰和相应的源在远端树突。可以得出结论，电场效应去极化，从而在这些afterdischarge神经元。（400字处截断摘要）
Afterdischarges elicited by antidromic stimulation were studied in the CA1 region of transverse slices of rat hippocampus. The slices were incubated in a static bathing medium containing Mn2+ with lowered Ca2+ concentration, which blocked chemical synaptic transmission. Extracellular voltage recordings from micropipettes revealed afterdischarges of population spikes, which represent synchronized action potentials. Afterdischarge duration became longer with incubation time, occasionally lasting up to 9 s. Simultaneous recordings from three extracellular micropipettes indicated propagation of individual population spikes along the CA1 cell body layer during an afterdischarge. Intracellular recordings from pyramidal cells showed that action potentials were synchronized with population spikes. When initial action potentials of an afterdischarge were blocked by hyperpolarizing the impaled cell, subsequent action potentials remained synchronized with population spikes, indicating a synchronizing interaction between neurons. Intrasomatic neuronal recordings sometimes revealed partial action potentials that were also synchronized with population spikes. During afterdischarges, relatively weak (10 mV) hyperpolarization blocked both full and partial action potentials. These observations suggest that synchronized action potentials and partial spikes were initiated near the soma. Intracellular voltage recordings were referenced to a local extracellular microelectrode in order to determine more accurately the transmembrane potential in the presence of large population spikes .54). Such neuronal recordings revealed brief transmembrane depolarizations that occurred synchronously with population spikes. Large injected hyperpolarizing currents did not affect the brief transmembrane depolarizations. Similar differential voltage recordings across glial cell membranes did not show measurable brief transmembrane depolarizations during population spikes. However, slow glial depolarizations during afterdischarges indicated prolonged K+ accumulation and clearance in the extracellular space, which probably contributed to the hyperexcitability of pyramidal cells. During an afterdischarge, extracellular potentials were recorded simultaneously from six micropipettes arranged perpendicularly to the stratum pyramidale. Current source-density analysis indicated a sink in the cell body layer during population spikes and a corresponding source in distal dendrites. It is concluded that an electrical field effect depolarizes and thus synchronizes neurons during these afterdischarges.(ABSTRACT TRUNCATED AT 400 WORDS)