FEEDFORWARD DENDRITIC INHIBITION IN RAT HIPPOCAMPAL PYRAMIDAL CELLS STUDIED INVITRO
FEEDFORWARD DENDRITIC INHIBITION IN RAT HIPPOCAMPAL PYRAMIDAL CELLS STUDIED INVITRO
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DOI：
10.1113/jphysiol.1982.sp014255
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发表时间：
1982-01-01
影响因子：
5.5
通讯作者：
NICOLL, RA
中科院分区：
文献类型：
--
作者：
ALGER, BE;NICOLL, RA
本实验采用大鼠海马脑片CA 1区锥体细胞的细胞内记录，研究了海马突触抑制的神经通路。当在单个锥体细胞中进行直接比较时，递送到层的顺向刺激。发现在正常记录条件下的辐射比逆向刺激在产生抑制性突触后电位（IPSP）方面更有效。正常情况下顺向ipsp表现为复杂的多相事件，而逆向ipsp则相对简单。顺向ipsp涉及GABA介导的树突状成分和非GABA介导的成分，两者都不被逆向刺激激活。巴比妥类药物诱导顺向反应的晚期去极化相，即去极化ipsp，其由GABA介导。逆向刺激不产生去极化ipsp。注射河豚毒素和荷包牡丹碱甲碘本地化的体细胞或顶端树突区域显示，去极化ipsp是由GABA释放的神经元元件在树突领域的锥体细胞树突上的行为。去极化ipsp是强烈的温度依赖性的，并且随着切片从37 - 22 ℃冷却，其幅度和持续时间逐渐增加。C.顺向刺激可产生去极化ipsp。在S中也是如此。辐射状在每一种情况下，去极化ipsp出现本地化的树突在外地刺激。在巴比妥类药物存在下，去极化ipsp明显是由GABA的相同突触释放引起的，GABA在正常情况下产生超极化树突ipsp。顺向和逆向刺激之间的大量比较表明，树突ipsp是通过前馈途径激活的。
Intracellular recordings from CA1 pyramidal cells in the rat hippocampal slice preparation were used to study the neuronal pathways involved in hippocampal synaptic inhibition. When direct comparisons are made in a single pyramidal cell, orthodromic stimulation delivered to stratum (s.) radiatum in normal recording conditions is found to be more effective then antidromic stimulation in producing inhibitory post-synaptic potentials (ipsp). Orthodromic ipsp in normal conditions appear to be complex, multiphasic events, whereas antidromic ipsp are relatively simple. The orthodromic ipsp involves both a GABA-mediated dendritic component and a non-GABA-mediated component neither of which is activated by antidromic stimulation. Barbiturates induce a late depolarizing phase of the orthodromic response, a depolarizing ipsp, which is mediated by GABA. The depolarizing ipsp is not produced by antidromic stimulation. Injections of tetrodotoxin and bicuculline methiodide localized to either somatic or apical dendritic regions reveal that the depolarizing ipsp is produced by GABA released from neuronal elements in the dendritic field which acts on pyramidal cell dendrites. The depolarizing ipsp is strongly temperature-dependent and increases in amplitude and duration progressively as slices are cooled from 37-22.degree. C. Depolarizing ipsp can be produced by orthodromic stimulation is s. oriens as well as in s. radiatum. In each case the depolarizing ipsp appear localized to the dendrites in the field stimulated. The depolarizing ipsp evident in the presence of barbiturates is caused by the same synaptic release of GABA which in normal conditions produces hyperpolarizing dendritic ipsp. Numerous comparisons between orthodromic and antidromic stimulation indicate that dendritic ipsp are activated by feed-forward pathways.