Elezgarai I, Díez J, Puente N, Azkue J J, Benítez R, Bilbao A, Knöpfel T, Doñate-Oliver F, Grandes P
Department of Neurosciences, Faculty of Medicine and Dentistry, Basque Country University, 699-48080 Bilbao, Spain.
Neuroscience. 2003;118(4):889-98. doi: 10.1016/s0306-4522(03)00068-x.
A pre-embedding immunocytochemical method was used to study the subcellular distribution of the voltage-dependent potassium channel Kv3.1b in the medial nucleus of the trapezoid body (MNTB) in developing and adult rat. The main finding was the localization of the channel in specific membrane compartments of the calyces of Held and principal globular neurons. Thus, at postnatal day (P) 9 immunoparticles were densely localized in plasma membranes of globular cell bodies and their main dendrites. At P16, a strong Kv3.1b labeling was still observed in these globular cell compartments, but the most remarkable feature was the presence of immunoparticles in synaptic terminal membranes of the calyces of Held. However, the presynaptic and postsynaptic specializations of the calyx of Held-globular cell synapses were virtually devoid of immunoparticles. This same subcellular distribution of Kv3.1b was seen in adult, with membranes of calycine terminals more uniformly labeled. The developmental profile of Kv3.1b expression in MNTB coincides with the functional maturation of the calyx of Held-principal globular neuron synapse. The presence of the channel in this system is crucial for the high-frequency synaptic transmission of auditory signals.
采用预包埋免疫细胞化学方法，研究发育中和成年大鼠梯形体内侧核（MNTB）中电压依赖性钾通道Kv3.1b的亚细胞分布。主要发现是该通道定位于Held壶腹和主要球状神经元的特定膜区室。因此，在出生后第9天（P9），免疫颗粒密集地定位于球状细胞体及其主要树突的质膜中。在P16时，在这些球状细胞区室中仍观察到强烈的Kv3.1b标记，但最显著的特征是在Held壶腹的突触终末膜中存在免疫颗粒。然而，Held壶腹-球状细胞突触的突触前和突触后特化几乎没有免疫颗粒。在成年大鼠中也观察到Kv3.1b相同的亚细胞分布，壶腹终末膜的标记更为均匀。MNTB中Kv3.1b表达的发育情况与Held壶腹-主要球状神经元突触的功能成熟相一致。该通道在该系统中的存在对于听觉信号的高频突触传递至关重要。
