MUSCARINIC AMPLIFICATION OF FAST EXCITATION IN HILAR NEURONS AND INHIBITION IN GRANULE CELLS IN THE GUINEA-PIG HIPPOCAMPUS
MUSCARINIC AMPLIFICATION OF FAST EXCITATION IN HILAR NEURONS AND INHIBITION IN GRANULE CELLS IN THE GUINEA-PIG HIPPOCAMPUS
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DOI：
10.1113/jphysiol.1994.sp020380
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发表时间：
1994-11-01
影响因子：
5.5
通讯作者：
MISGELD, U
中科院分区：
文献类型：
--
作者：
BRUNNER, H;MISGELD, U
1.在豚鼠海马片上，用细胞内记录的方法研究了胆碱能激动剂卡巴胆碱(CCH)或乙酰胆碱酯酶抑制剂艾司林对推测抑制的肺门神经元和颗粒细胞抑制的影响。CCH(1-5 mU/M)可显著增强肺门神经元的放电活动，增强颗粒细胞自发和诱发的IPSP。依色林以阿托品敏感的方式，通过影响膜特性和兴奋性突触堵塞来增加肺门神经元的兴奋性。EPSPS很容易触发持续时间较长的爆发放电。在颗粒细胞中，诱发的GABA(A)和GABA(B)受体介导的IPSP的幅度增强。在eserine和谷氨酸和GABA能突触传递拮抗剂存在的情况下，训练刺激可诱发阿托品敏感的慢EPSP。与颗粒细胞不同，肺门神经元中慢的EPSP总是先于强烈的超极化后爆发。我们认为，隔-海马区纤维释放的乙酰胆碱能增强抑制性肺门神经元的快速突触兴奋和颗粒细胞的抑制。在齿状区，从慢的EPSP的时间进程来看，M受体介导的效应比预期的要快。
1. Effects of the cholinergic agonist, carbachol (CCh), or the acetylcholinesterase inhibitor, eserine, on presumed inhibitory hilar neurones and on inhibition in granule cells were studied by intracellular recording in guinea-pig hippocampal slices.2. CCh (1-5 mu M) strongly enhanced the discharge activity of hilar neurones and spontaneous and evoked IPSPs in granule cells.3. Eserine, in an atropine-sensitive manner, increased the excitability of hilar neurones through effects on membrane properties and on excitatory synaptic barrage. EPSPs readily triggered long-duration burst discharges. In granule cells, the amplitudes of evoked GABA(A), and GABA(B) receptor-mediated IPSPs were enhanced.4. In the presence of eserine and antagonists for glutamatergic and GABAergic synaptic transmission, train stimulation evoked atropine-sensitive slow EPSPs. In contrast to those in granule cells, slow EPSPs in hilar neurones were invariably preceded by a strong burst-after-hyperpolarization.5. We suggest that acetylcholine, released from septo-hippocampal fibres, amplifies fast synaptic excitation of inhibitory hilar neurones and inhibition of granule cells. In the dentate area, muscarinic receptor-mediated effects are faster than anticipated from the time course of the slow EPSP.