Rosenberger Melissa H, Fremouw Thane, Casseday John H, Covey Ellen
Department of Psychology, University of Washington, Seattle 98195, USA.
J Comp Neurol. 2003 Jul 14;462(1):101-20. doi: 10.1002/cne.10713.
Voltage-gated potassium channels play an important role in shaping membrane properties that underlie neurons' discharge patterns and the ways in which they transform their input. In the auditory system, low threshold potassium currents such as those created by Kv1.1 subunits contribute to precise phaselocking and to transient onset responses that provide time markers for temporal features of sounds. The purpose of the present study was to compare information about the distribution of neurons expressing the KV 1.1 in the brainstem auditory nuclei with the distribution of neurons with known functional properties in the auditory system of the big brown bat, Eptesicus fuscus. We used immunocytochemistry and light microscopy to look at the distribution of Kv1.1 subunits in the brainstem auditory nuclei. There was prominent expression in cell types known to contain high levels of Kv1.1 in other species and known to respond to auditory signals with high temporal precision. These included octopus cells and spherical bushy cells of the cochlear nucleus and principal neurons of the medial nucleus of the trapezoid body. In addition, we found high levels of Kv1.1 in neurons of the columnar subdivision of the ventral nucleus of the lateral lemniscus and in ventral periolivary cell groups. Neurons with high levels of Kv1.1 were differentially distributed in the intermediate nucleus of the lateral lemniscus and in the inferior colliculus, suggesting that these structures contain functionally distinct cell populations, some of which may be involved in high-precision temporal processing.
电压门控钾通道在塑造膜特性方面发挥着重要作用，而这些膜特性是神经元放电模式及其转换输入方式的基础。在听觉系统中，低阈值钾电流（如由Kv1.1亚基产生的电流）有助于精确的锁相以及瞬态起始反应，这些反应为声音的时间特征提供时间标记。本研究的目的是比较大棕蝠（棕蝠）听觉系统中表达KV 1.1的神经元在脑干听觉核中的分布信息与具有已知功能特性的神经元的分布情况。我们使用免疫细胞化学和光学显微镜来观察Kv1.1亚基在脑干听觉核中的分布。在其他物种中已知含有高水平Kv1.1且已知能以高时间精度对听觉信号做出反应的细胞类型中，有显著表达。这些细胞包括耳蜗核的章鱼细胞和球形浓密细胞以及梯形体内侧核的主要神经元。此外，我们在外侧丘系腹侧核的柱状亚区神经元和腹侧橄榄周细胞群中发现了高水平的Kv1.1。Kv1.1水平高的神经元在外侧丘系中间核和下丘中分布不同，这表明这些结构包含功能不同的细胞群体，其中一些可能参与高精度的时间处理。
