PROPERTIES OF INHIBITORY AND EXCITATORY SYNAPSES BETWEEN HIPPOCAMPAL-NEURONS IN VERY-LOW-DENSITY CULTURES
PROPERTIES OF INHIBITORY AND EXCITATORY SYNAPSES BETWEEN HIPPOCAMPAL-NEURONS IN VERY-LOW-DENSITY CULTURES
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DOI：
10.1002/syn.890180206
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发表时间：
1994-10-01
期刊：
影响因子：
2.3
通讯作者：
DICHTER, MA
中科院分区：
文献类型：
--
作者：
WILCOX, KS;BUCHHALTER, J;DICHTER, MA
整个细胞贴片夹技术用于检查以非常低密度（VLD）培养的制剂保持的胚胎海马神经元的电生理特性。这些实验的目的是建立VLD培养物作为模型系统的可行性，在该模型系统中，在没有多突触神经支配的情况下，在单个单突触连接下研究神经传递的调节。神经元在VLD培养物中的去极化揭示了电压依赖性钠，钙和钾电流，分别被四毒素（TTX），钴和四乙基氨基和四氨基吡啶阻塞。当同时记录神经元对时，突触前神经元中引起的动作电位分别引起兴奋性或抑制性突触后电流（EPSCS或IPSC）。双重成分EPSC是由于两种类型的突触后，离子谷氨酸受体的激活：N-甲基-D-天冬氨酸（NMDA）和非NMDA受体。引起的IPSC是由于突触后γ-氨基丁酸（GABA）受体的激活所致。兴奋性和抑制性突触都响应于高频刺激而表现出短期抑郁症，尽管IPSC通常比EPSC更大的程度降低了。发现自发的微型EPSC和IPSC在TTX中持续存在，被相同的药理学拮抗剂阻塞，这些药理学拮抗剂阻断了诱发反应，响应高渗透溶液的频率增加，并且不受细胞外钙浓度的变化，MIPSC发生在MIPSC中，在某种程度上发生在A.频率明显低于MEPSC。这些实验表明，VLD培养物中的神经传递是以与量化假设一致的方式发生的，因此，VLD培养是研究孤立神经元之间研究兴奋性和抑制性神经传递的良好模型。此外，在可比的生理条件下进行的这些实验表明，兴奋性和抑制性神经元之间神经递质释放的基本差异。 （c）1994 Wiley-Liss，Inc。
The whole cell patch clamp technique was used to examine the electrophysiological properties of embryonic hippocampal neurons maintained in a very low density (VLD) culture preparation. The goal of these experiments was to establish the viability of the VLD culture as a model system in which to study regulation of neurotransmission at single monosynaptic connections, in the absence of polysynaptic innervation. Depolarization of neurons in the VLD culture revealed voltage-dependent sodium, calcium, and potassium currents which were blocked with, respectively, tetrodotoxin (TTX), cobalt, and tetraethylammonium and 4-aminopyridine. When pairs of neurons were simultaneously recorded, action potentials evoked in presynaptic neurons elicited either excitatory or inhibitory postsynaptic currents (EPSCs or IPSCs, respectively). The dual component EPSCs were due to the activation of both types of postsynaptic, ionotropic glutamate receptors: N-methyl-D-aspartate (NMDA) and non-NMDA receptors. Evoked IPSCs were due to the activation of postsynaptic gamma-aminobutyric acid (GABA) receptors. Both excitatory and inhibitory synapses exhibited short term depression in response to high frequency stimulation, although IPSCs were routinely decreased to a much greater degree than EPSCs. Spontaneous miniature EPSCs and IPSCs were found to persist in TTX, were blocked by the same pharmacological antagonists which blocked evoked responses, increased in frequency in response to hyperosmotic solution, and were unaffected by changes in extracellular calcium concentration, mIPSCS were found to occur at a significantly lower frequency than mEPSCs. These experiments indicated that neurotransmission in the VLD cultures occurs in a manner consistent with the quantal hypothesis and, therefore, the VLD culture is a good model for studying excitatory and inhibitory neurotransmission between isolated pairs of neurons. In addition, these experiments, performed under comparable physiological conditions, demonstrated that there are fundamental differences underlying neurotransmitter release between excitatory and inhibitory neurons. (C) 1994 Wiley-Liss, Inc.