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首页> 外文期刊>Journal of Neurophysiology >Synaptic inputs to stellate cells in the ventral cochlear nucleus.
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Synaptic inputs to stellate cells in the ventral cochlear nucleus.

机译：突触输入到腹侧耳蜗核中的星状细胞。

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摘要

Auditory information is carried from the cochlear nuclei to the inferior colliculi through six parallel ascending pathways, one of which is through stellate cells of the ventral cochlear nuclei (VCN) through the trapezoid body. To characterize and identify the synaptic influences on T stellate cells, intracellular recordings were made from anatomically identified stellate cells in parasagittal slices of murine cochlear nuclei. Shocks to the auditory nerve consistently evoked five types of synaptic responses in T stellate cells, which reflect sources intrinsic to the cochlear nuclear complex. 1) Monosynaptic excitatory postsynaptic potentials (EPSPs) that were blocked by 6,7-dinitroquinoxaline-2,3-dione (DNQX), an antagonist of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, probably reflected activation by auditory nerve fibers. Electrophysiological estimates indicate that about five auditory nerve fibers converge on one T stellate cell. 2) Disynaptic, glycinergic inhibitory postsynaptic potentials (IPSPs) arise through inhibitory interneurons in the VCN or in the dorsal cochlear nucleus (DCN). 3) Slow depolarizations, the source of which has not been identified, that lasted between 0.2 and 1 s and were blocked by -2-amino-5-phosphonovaleric acid (APV), the N-methyl-D-aspartate (NMDA) receptor antagonist. 4) Rapid, late glutamatergic EPSPs are polysynaptic and may arise from other T stellate cells. 5) Trains of late glycinergic IPSPs after single or repetitive shocks match the responses of D stellate cells, showing that D stellate cells are one source of glycinergic inhibition to T stellate cells. The source of late, polysynaptic EPSPs and IPSPs was assessed electrophysiologically and pharmacologically. Late synaptic responses in T stellate cells were enhanced by repetitive stimulation, indicating that the interneurons from which they arose should fire trains of action potentials in responses to trains of shocks. Late EPSPs and late IPSPs were blocked by APV and enhanced by the removal of Mg2+, indicating that the interneurons were driven at least in part through NMDA receptors. Bicuculline, a gamma-aminobutyric acid-A (GABAA) receptor antagonist, enhanced the late PSPs, indicating that GABAergic inhibition suppresses both the glycinergic interneurons responsible for the trains of IPSPs in T-stellate cells and the interneuron responsible for late EPSPs in T stellate cells. The glycinergic interneurons that mediate the series of IPSPs are intrinsic to the ventral cochlear nucleus because long series of IPSPs were recorded from T stellate cells in slices in which the DCN was removed. These experiments indicate that T stellate cells are a potential source of late EPSPs and that D stellate cells are a potential source for trains of late IPSPs.
机译：听觉信息通过六个平行的上升途径从耳蜗核传递至下丘脑，其中一个途径是通过梯形体通过腹侧耳蜗核（VCN）的星状细胞。为了表征和鉴定突触对T星状细胞的影响，从解剖学上鉴定的鼠耳蜗旁矢状位片中的星状细胞进行了细胞内记录。听神经的电击持续引起T星状细胞中五种类型的突触反应，这反映了耳蜗核复合体的内在来源。 1）被6,7-二硝基喹喔啉-2,3-二酮（DNQX）（α-氨基-3-羟基-5-羟基-5-甲基-4-异恶唑丙酸受体的拮抗剂）阻断的单突触兴奋性突触后电位（EPSP）反映听神经纤维的激活。电生理学估计表明，大约5条听觉神经纤维会聚在一个T星状细胞上。 2）突触，甘氨酸抑制性突触后电位（IPSP）通过VCN或背侧耳蜗核（DCN）中的抑制性中间神经元产生。 3）持续持续0.2到1 s的缓慢去极化作用，持续时间为0.2到1 s，并被N-甲基-D-天冬氨酸（NMDA）受体-2-氨基-5-膦酰戊酸（APV）阻断拮抗剂。 4）快速的晚期谷氨酸能EPSP是多突触的，可能来自其他T星状细胞。 5）单次或重复性电击后的晚期甘氨酸IPSPs序列与D星状细胞的反应相匹配，表明D星状细胞是对T星状细胞进行糖氨酸抑制的一种来源。电生理学和药理学评估了晚期多突触EPSPs和IPSPs的来源。重复刺激增强了T星状细胞中的晚期突触反应，表明它们产生的中间神经元应激发一系列动作电位，以响应一系列电击。晚期EPSP和晚期IPSP被APV阻断，并由于Mg2 +的去除而增强，表明中间神经元至少部分地由NMDA受体驱动。 Bicuculline是一种γ-氨基丁酸-A（GABAA）受体拮抗剂，可增强晚期PSP，这表明GABA能抑制作用既抑制了T星状细胞中负责IPSP的甘氨酸能中间神经元，也抑制了T星状细胞中负责晚期EPSP的中间神经元。细胞。介导一系列IPSP的甘氨酸能神经元是腹侧耳蜗核固有的，因为在去除DCN的切片中，T星状细胞记录了长系列IPSP。这些实验表明，T星状细胞是晚期EPSP的潜在来源，而D星状细胞是一系列后期IPSP的潜在来源。

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