Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
Neuroimage. 2011 Oct 1;58(3):761-9. doi: 10.1016/j.neuroimage.2011.07.003. Epub 2011 Jul 20.
Neuronal M-channels are low threshold, slowly activating and non-inactivating, voltage dependent K(+) channels that play a crucial role in controlling neuronal excitability. The native M-channel is composed of heteromeric or homomeric assemblies of subunits belonging to the Kv7/KCNQ family, with KCNQ2/3 heteromers being the most abundant form. KCNQ2 and KCNQ3 subunits have been found to be expressed in various neurons in the central and peripheral nervous system of rodents and humans. Previous evidence shows preferential localization of both subunits to axon initial segments, somata and nodes of Ranvier. In this work, we show the distribution and co-localization of KCNQ2 and KCNQ3 subunits throughout the hippocampal formation, via immunostaining experiments on unfixed rat brain slices and confocal microscopy. We find intense localization and colocalization to the axonal initial segment in several regions of the hippocampus, as well as staining for non-neuronal cells in the area of the lateral ventricle. We did not observe colocalization of KCNQ2 or KCNQ3 with the presynaptic protein, synaptophysin.
神经元 M 型通道是一种低阈值、缓慢激活且非失活的电压依赖性 K(+)通道，在控制神经元兴奋性方面发挥着关键作用。天然的 M 型通道由属于 Kv7/KCNQ 家族的亚基异源或同源组装而成，其中 KCNQ2/3 异源二聚体是最丰富的形式。KCNQ2 和 KCNQ3 亚基已被发现在啮齿动物和人类中枢和周围神经系统的各种神经元中表达。先前的证据表明，这两个亚基优先定位于轴突起始段、胞体和郎飞结。在这项工作中，我们通过对未固定的大鼠脑切片进行免疫染色实验和共聚焦显微镜观察，展示了 KCNQ2 和 KCNQ3 亚基在海马结构中的分布和共定位。我们发现，在海马的几个区域，KCNQ2 和 KCNQ3 与轴突起始段的强烈定位和共定位，以及在侧脑室区域的非神经元细胞的染色。我们没有观察到 KCNQ2 或 KCNQ3 与突触前蛋白突触小泡蛋白的共定位。
