PHYSIOLOGY AND PHARMACOLOGY OF UNITARY SYNAPTIC CONNECTIONS BETWEEN PAIRS OF CELLS IN AREAS CA3 AND CA1 OF RAT HIPPOCAMPAL SLICE CULTURES
PHYSIOLOGY AND PHARMACOLOGY OF UNITARY SYNAPTIC CONNECTIONS BETWEEN PAIRS OF CELLS IN AREAS CA3 AND CA1 OF RAT HIPPOCAMPAL SLICE CULTURES
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DOI：
10.1152/jn.1995.73.3.1282
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发表时间：
1995-03-01
影响因子：
2.5
通讯作者：
THOMPSON, SM
中科院分区：
文献类型：
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作者：
DEBANNE, D;GUERINEAU, NC;THOMPSON, SM
1.在培养的大鼠海马脑片上，分别用尖微电极和全细胞膜片钳技术进行成对细胞内记录。研究了锥体细胞和非锥体细胞之间以及CA 1和CA3.2区之间的单一突触连接。CA 3区锥体神经元之间的单突触兴奋性突触反应被发现在56%的细胞对（n = 91，28突触后细胞）。从CA 3细胞到CA 1细胞的单突触连接在76%的细胞对中观察到（n = 125，26突触后细胞）。而从CA 1到CA 3的神经元仅占8%的细胞对（n = 13，13突触后细胞）。单突触兴奋性连接仅见于16%的CA 1/CA 1细胞对（n = 25，其中10个突触后细胞）. CA 3-CA 1锥体细胞对之间的突触抑制率为2%，而CA 3-CA 1锥体细胞对之间的突触抑制率为43%。在50%的CA 3锥体细胞对。两个细胞中的同步抑制性突触后电位（IPSP）可以由一个锥体细胞中的动作电位触发。CA3.4区内75%的中间神经元和锥体细胞对之间存在相互的单突触连接。单突触CA 3-CA 1-细胞反应的潜伏期明显长于两个CA 3细胞之间的反应。在CA 3区内，中间神经元与锥体细胞之间的抑制性突触反应的潜伏期显著短于锥体细胞之间的兴奋性突触反应的潜伏期，中间神经元的单突触兴奋性突触后电位（EPSP）的达峰时间显著短于锥体神经元.在CA 3-CA 3和CA 3-CA 1锥体细胞对的单一单突触EPSP中鉴定了6-氰基-7-硝基喹喔啉-2，3-二酮（CNQX）和D-2-氨基-5-膦酰基戊酸（APS）敏感成分。CNQX敏感成分的平均达峰时间和持续时间分别为6.2 +/- 0.3（SE）ms和61.2 +/- 2.0 ms，振幅与1 mV相似（n = 93）。只有当细胞相对于静息电位去极化时，才能检测到EPSP的APS敏感成分，平均Rime-to-peak为41 +/- 5 ms，持续时间为121 +/- 1.1 ms（n = 6），并且随着突触后去极化，振幅增加。中间神经元和锥体细胞之间的单一单突触IPSP的平均振幅接近1 mV，并且被γ-氨基丁酸-A（GABA（A））受体拮抗剂完全阻断（n = 3）。单一的抑制反应，发现只有内，而不是之间，CA 3或CA 1区。孤立的IPSPs可以诱发成对的锥体细胞兴奋性氨基酸受体拮抗剂的存在下，只有当细胞外刺激电极位于同一海马领域的记录细胞。在区域CA 3和CA 1之间的边界处可以划定一个类似于380 μ m的区域，在该区域内，刺激在两个海马区域中诱发IPSP。由CA 3锥体细胞与CA 3或CA 1细胞形成的兴奋性突触同样有效，并且可以估计5-10个CA 3细胞必须在50 ms内活跃以激活共同的突触后锥体细胞。相反，单个中间神经元的放电足以抑制突触后锥体细胞的动作电位。
1. Paired intracellular recordings were mode in rat hippocampal slice cultures, with the use of either sharp microelectrodes or the whole cell configuration of thr patch-clamp technique. Unitary synaptic connections were studied between pyramidal and nonpyramidal cells within and between areas CA1 and CA3.2. Monosynaptic excitatory synaptic responses between CA3 pyramidal neurons were found in 56% of cell pairs (n = 91, 28 postsynaptic cells). Monosynaptic connections from a CA3 cell to a CA1 cell were observed in 76% of cell pairs (n = 125, 26 postsynaptic cells). but from CA1 to CA3 neurons in only 8% of cell pairs (n = 13, 13 postsynaptic cells). Monosynaptic excitatory connections were found in only 16% of CA1/CA1 cell pairs (n = 25, 10 postsynaptic cells).3. Disynaptic inhibition was commonly observed between CA3 cell pairs (43%), but rarely found between CA3-CA1 pyramidal cell pairs (2%). In 50% of CA3 pyramidal cell pairs. synchronous inhibitory postsynaptic potentials (IPSPs) in both cells could be triggered by an action potential in one pyramidal cell. Reciprocal monosynaptic connections were found between 75% of interneuron and pyramidal cell pairs within area CA3.4. The latency of monosynaptic CA3- to CA1-cell responses was significantly longer than for responses between two CA3 cells. Within area CA3 the latencies for inhibitory synaptic responses between interneurons and pyramidal cells were significantly shorter than those for excitatory responses between pyramidal cells, Monosynaptic excitatory postsynaptic potentials (EPSPs) in interneurons had a significantly shorter time-to-peak than those recorded in pyramidal neurons.5. 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX)- and D-2-amino-5-phosphonovalerate (APS)-sensitive components were identified in unitary monosynaptic EPSPs in CA3-CA3 and CA3-CA1 pyramidal cell pairs. The CNQX-sensitive component had a mean time-to-peak and duration of 6.2 +/- 0.3 (SE) ms and 61.2 +/- 2.0 ms, respectively, and an amplitude of similar to 1 mV (n = 93). The APS-sensitive component of EPSPs was only detected when the cell was depolarized with respect to the resting potential, had a mean rime-to-peak of 41 +/- 5 ms and duration of 121 +/- 1.1 ms (n = 6), and increased in amplitude with postsynaptic depolarization.6. Unitary monosynaptic IPSPs between an interneuron and a pyramidal cell had a mean amplitude of similar to 1 mV and were fully blocked by gamma-aminobutyric acid-A (GABA(A)) receptor antagonists (n = 3).7. Unitary inhibitory responses were found only within, but not between, areas CA3 or CA1. Isolated IPSPs could be evoked in pairs of pyramidal cells in the presence of excitatory amino acid receptor antagonists only when the extracellular stimulating electrode was located within the same hippocampal field as the recorded cells. A zone of similar to 380 mu m could be delimited at the border between areas CA3 and CA1, within which stimulation evoked IPSPs in both hippocampal fields.8. Excitatory synapses formed by CA3 pyramidal cells with either CA3 or CA1 cells were equally effective, and it can be estimated that 5-10 CA3 cells must be active within 50 ms to activate a common postsynaptic pyramidal cell. In contrast, discharge in a single interneuron is sufficient to inhibit action potentials in a postsynaptic pyramidal cell.