Position-dependent patterning of spontaneous action potentials in immature cochlear inner hair cells.-猫眼课题宝

DOI：

10.1038/nn.2803

发表时间：

2011-06

期刊：

NATURE NEUROSCIENCE

影响因子：

通讯作者：

中科院分区：

医学1区

文献类型：

作者：

Johnson, Stuart L.;Eckrich, Tobias;Kuhn, Stephanie;Zampini, Valeria;Franz, Christoph;Ranatunga, Kishani M.;Roberts, Terri P.;Masetto, Sergio;Knipper, Marlies;Kros, Corne J.;Marcotti, Walter

来源链接：

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3103712/?report=classic

自发动作电位活动对哺乳动物感觉系统的发育至关重要。在听觉系统中，在未成熟的螺旋神经节细胞和脑干神经元中观察到了模式放电活动，这可能依赖于耳蜗内毛细胞(IHC)的动作电位。目前还不确定尖峰活动是否是发育中的IHC所固有的，以及它是否显示出图案化。我们发现，动作电位是由原始啮齿动物未成熟的IHC固有地产生的，顶端IHC表现出爆发性活动，而不是在基底细胞中更持续地放电。我们证明传出神经递质ACh，通过微调IHC的静息膜电位(Vm)，对顶端细胞的爆裂模式至关重要。内源性细胞外ATP也通过激活SK2通道参与心尖部和基底部IHC的Vm。我们推测，耳蜗区放电模式的不同导致了IHC和听觉通路的纯音分化。

Spontaneous action potential activity is crucial for mammalian sensory system development. In the auditory system, patterned firing activity has been observed in immature spiral ganglion cells and brain-stem neurons and is likely to depend on cochlear inner hair cell (IHC) action potentials. It remains uncertain whether spiking activity is intrinsic to developing IHCs and whether it shows patterning. We found that action potentials are intrinsically generated by immature IHCs of altricial rodents and that apical IHCs exhibit bursting activity as opposed to more sustained firing in basal cells. We show that the efferent neurotransmitter ACh, by fine-tuning the IHC’s resting membrane potential (Vm), is crucial for the bursting pattern in apical cells. Endogenous extracellular ATP also contributes to the Vm of apical and basal IHCs by activating SK2 channels. We hypothesize that the difference in firing pattern along the cochlea instructs the tonotopic differentiation of IHCs and auditory pathway.