Weiser M, Bueno E, Sekirnjak C, Martone M E, Baker H, Hillman D, Chen S, Thornhill W, Ellisman M, Rudy B
Department of Physiology and Neuroscience, New York University Medical Center, New York 10016, USA.
J Neurosci. 1995 Jun;15(6):4298-314. doi: 10.1523/JNEUROSCI.15-06-04298.1995.
Potassium channels play major roles in the regulation of many aspects of neuronal excitability. These channels are particularly well suited for such multiplicity of roles since there is a large diversity of channel types. This diversity contributes to the ability of specific neurons (and possibly different regions of the same neuron) to respond uniquely to a given input. Neuronal integration depends on the local response of spatially segregated inputs to the cell and the communication of these integration centers with the axon. Therefore, the functional implications of a given set of K+ channels varies depending on their precise location on the neuronal surface. Site-specific antibodies were utilized to characterize the distribution of KV3.1b, a subunit of voltage-gated K+ channels in CNS neurons. KV3.1b subunits are expressed in specific neuronal populations of the rat brain, such as cerebellar granule cells, projecting neurons of deep cerebellar nuclei, the substantia nigra pars-reticulata, the globus pallidus, and the ventral thalamus (reticular thalamic nucleus, ventral lateral geniculate and zona incerta). The KV3.1b protein is also present in various neuronal populations involved in the processing of auditory signals, including the inferior colliculus, the nuclei of the lateral lemniscus, the superior olive, and some parts of the cochlear nuclei; as well as in several other neuronal groups in the brainstem (e.g., in the oculomotor nucleus, the pontine nuclei, the reticulotegmental nucleus of the pons, trigeminal and vestibular nuclei, and the reticular formation) and subsets of neurons in the neocortex, the hippocampus and the caudate-putamen shown by double staining to correspond to neurons containing parvalbumin. KV3.1b subunits are localized predominantly in somatic and axonal membranes (particularly in axonal terminal fields) but are much less prominent in dendritic arborizations. This distribution is different than that of other subunits of voltage gated K+ channels and is consistent with a role in the modulation of action potentials. KV3.1b proteins have a cellular and subcellular distribution different than the related KV3.2 subunits which express in Xenopus oocytes currents similar to those expressed by KV3.1b.
钾通道在调节神经元兴奋性的诸多方面发挥着主要作用。这些通道特别适合承担如此多样的角色，因为通道类型多种多样。这种多样性有助于特定神经元（可能还有同一神经元的不同区域）对给定输入做出独特反应。神经元整合取决于空间上分离的输入对细胞的局部反应以及这些整合中心与轴突之间的通信。因此，特定一组钾通道的功能影响因其在神经元表面的精确位置而异。利用位点特异性抗体来表征中枢神经系统神经元中电压门控钾通道亚基KV3.1b的分布。KV3.1b亚基在大鼠脑的特定神经元群体中表达，如小脑颗粒细胞、小脑深部核团的投射神经元、黑质网状部、苍白球和腹侧丘脑（丘脑网状核、腹侧外侧膝状体和未定带）。KV3.1b蛋白也存在于参与听觉信号处理的各种神经元群体中，包括下丘、外侧丘系核、上橄榄核和耳蜗核的某些部分；以及脑干中的其他几个神经元群（例如，动眼神经核、脑桥核、脑桥网状被盖核、三叉神经核和前庭核以及网状结构），并且通过双重染色显示新皮层、海马体和尾状核 - 壳核中的神经元子集与含有小白蛋白的神经元相对应。KV3.1b亚基主要定位于体细胞和轴突膜（特别是在轴突终末场），但在树突分支中不太明显。这种分布与电压门控钾通道的其他亚基不同，并且与动作电位的调节作用一致。KV3.1b蛋白的细胞和亚细胞分布与相关的KV3.2亚基不同，后者在非洲爪蟾卵母细胞中表达的电流与KV3.1b表达的电流相似。
