Glomerular synaptic responses to olfactory nerve input in rat olfactory bulb slices
Glomerular synaptic responses to olfactory nerve input in rat olfactory bulb slices
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DOI：
10.1016/s0306-4522(96)00706-3
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发表时间：
1997-07-01
期刊：
影响因子：
3.3
通讯作者：
Shipley, MT
中科院分区：
文献类型：
--
作者：
AroniadouAnderjaska, V;Ennis, M;Shipley, MT
在幼龄大鼠嗅球片中，刺激嗅神经层在肾小球层诱发的场电位由两种负组分组成：一种是早期组分（N1），该组分被水浴应用kainateiamino-3-hydroxy-5-methyl-4-异恶唑olepropionic acid （AMPA）受体拮抗剂6-cyano-7-nitroquinoxaline-2,3-dione （CNQX, 10 μ M）阻断；持续时间大于或等于350微秒)由CNQX影响,增强了减少Mg2 +在中,并被n -甲基- d受体拮抗剂DL-2-amino-5-phosphonovalerate(50μM)肾小球场势的比较之前和之后刀削减孤立肾小球层深层的嗅球表示,N1和N2都是由电流产生的,在大多数情况下,在肾小球内。在标准介质或CNQX存在的情况下，对嗅觉神经刺激引起的保持电位谱进行层流分析，发现N1和N2在外丛状细胞层和二尖瓣细胞层中极性反转，表明这两种成分反映了二尖瓣细胞/簇状细胞远端根尖树突的突触反应。同时在肾小球层和二尖瓣细胞层记录的场电位显示：(i) N1与二尖瓣细胞短暂的、短潜伏期的尖峰活动有关，（ii） N2与延长的二尖瓣细胞尖峰活动有关，因为N2和晚期细胞放电具有相似的时间过程，并且两者都被应用dl -2-氨基-5-磷酸戊酸盐阻断。GABA(A)受体拮抗剂双库兰（10 μ M）在标准培养基中选择性增强N2。dl -2-氨基-5-磷酸戊酸显著降低了增强的N2。士的宁，一种甘氨酸受体拮抗剂，具有与双藤碱相似的作用，但只有在高浓度时才被证明可以阻断GABA(A)受体；低浓度士的宁对其无影响。所有测试药物的效果都是可逆的。在大鼠嗅球中，嗅觉神经的激活在二尖瓣细胞/簇状细胞的远端根尖树突中引发了盐酸盐/AMPA受体介导的反应，随后是一个缓慢的n -甲基- d -天冬氨酸受体介导的反应，引发二尖瓣细胞的长时间放电。GABA，受体介导的抑制似乎优先抑制这种n -甲基- d -天冬氨酸受体介导的成分。嗅觉系统初级突触中n -甲基- d -天冬氨酸受体介导的突触后活性的延长可能通过促进突触整合和可塑性在嗅觉加工中发挥关键作用。(c) 1997年。Elsevier Science Ltd.出版。
In olfactory bulb slices from young rats, the field potential evoked in the glomerular layer by stimulation in the olfactory nerve layer consisted of two negative components: an early component (N1) which was blocked by bath application of the kainateiamino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 mu M), and a late, prolonged component (N2; duration greater than or equal to 350 msec) which was unaffected by CNQX, was enhanced by reduction of Mg2+ in the medium, and was blocked by the N-methyl-D-aspartate receptor antagonist DL-2-amino-5-phosphonovalerate (50 mu M) A comparison of the glomerular field potentials before and after knife cuts that isolated the glomerular layer from the deeper layers of the olfactory bulb indicated that both N1 and N2 were produced by currents generated, for the most part, within the glomeruli. A laminar analysis of the held potential profiles evoked by olfactory nerve stimulation in standard medium, or in the presence of CNQX, showed that N1 and N2 reversed polarity in the external plexiform and mitral cell layers, suggesting that both components reflected synaptic responses in the distal, apical dendrites of mitral/tufted cells. Simultaneous field potential recordings in the glomerular layer and intracellular recordings in the mitral cell layer showed that: (i) N1 is associated with a brief, short-latency spiking activity of mitral cells, and (ii) N2 is associated with prolonged mitral cell spiking, since N2 and the late cell firing had similar time-courses, and both were blocked by bath applied DL-2-amino-5-phosphonovalerate.Application of the GABA(A) receptor antagonist bicuculline methiodide (10 mu M) to standard medium selectively enhanced N2. The enhanced N2 was significantly reduced by DL-2-amino-5-phosphonovalerate. Strychnine, an antagonist of glycine receptors, had similar effects to those of bicuculline, but only at high concentrations that have been previously shown to block GABA(A) receptors; al low concentrations strychnine had no effect. The effects of all drugs tested were reversible.In the rat olfactory bulb, activation of the olfactory nerve evokes a kainate/AMPA receptor-mediated response in the distal, apical dendrites of mitral/tufted cells, followed by a slow N-methyl-D-aspartate receptor-mediated response which triggers prolonged discharge of mitral cells. GABA, receptor-mediated inhibition appears to suppress, preferentially, this N-methyl-D-aspartate receptor-mediated component. The presence of prolonged N-methyl-D-aspartate receptor-mediated postsynaptic activity at the primary synapses of the olfactory system may play a key role in olfactory processing by facilitating synaptic integration and plasticity. (C) 1997 IBRO. Published by Elsevier Science Ltd.