Hyperpolarization-Activated Currents and Subthreshold Resonance in Granule Cells of the Olfactory Bulb.
Hyperpolarization-Activated Currents and Subthreshold Resonance in Granule Cells of the Olfactory Bulb.
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DOI：
10.1523/eneuro.0197-16.2016
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发表时间：
2016-09
期刊：
影响因子：
3.4
通讯作者：
Araneda RC
中科院分区：
文献类型：
--
作者：
Hu R;Ferguson KA;Whiteus CB;Meijer DH;Araneda RC
神经回路振荡动力学的一个重要贡献是超极化激活电流（Ih）的持续激活和失活。网络同步动力学在主嗅球（MOB）和副嗅球（AOB）对气味信号的初始处理中起着重要作用。在小鼠嗅球中，我们发现Ih存在于嗅球中最突出的抑制神经元颗粒细胞（GCs）中，并且Ih是GCs阈下共振的基础。与Ih的性质一致，电流对胞外K+浓度和Ih阻滞剂ZD7288（4-乙基苯基氨基-1,2-二甲基-6-甲基氨基嘧啶氯）的变化表现出敏感性。ZD7288还引起gc超极化，增加其输入电阻，表明Ih在gc中处于静止状态。在细胞内溶液中加入cAMP可将Ih的激活转移到MOB中负电位较低的区域，但在AOB中没有，这表明不同亚基组成的通道介导了这些区域的Ih。此外，我们发现成熟的gc在θ频率范围（4-12 Hz）表现出h依赖的亚阈值共振。MOB中的另一种抑制性亚型，即球膜周围细胞，在δ波范围（1-4 Hz）表现出h依赖性阈下共振，而主要神经元，即二尖瓣细胞，则不表现出h依赖性阈下共振。重要的是，脑皮层中Ih的大小，以及共振的强度和频率，都表现出出生后的发育进程，这表明脑皮层中Ih的发展可能不同地促进了它们对感觉输入的整合和对振荡电路动力学的贡献。
An important contribution to neural circuit oscillatory dynamics is the ongoing activation and inactivation of hyperpolarization-activated currents (Ih). Network synchrony dynamics play an important role in the initial processing of odor signals by the main olfactory bulb (MOB) and accessory olfactory bulb (AOB). In the mouse olfactory bulb, we show that Ih is present in granule cells (GCs), the most prominent inhibitory neuron in the olfactory bulb, and that Ih underlies subthreshold resonance in GCs. In accord with the properties of Ih, the currents exhibited sensitivity to changes in extracellular K+ concentration and ZD7288 (4-ethylphenylamino-1,2-dimethyl-6-methylaminopyrimidin chloride), a blocker of Ih. ZD7288 also caused GCs to hyperpolarize and increase their input resistance, suggesting that Ih is active at rest in GCs. The inclusion of cAMP in the intracellular solution shifted the activation of Ih to less negative potentials in the MOB, but not in the AOB, suggesting that channels with different subunit composition mediate Ih in these regions. Furthermore, we show that mature GCs exhibit Ih-dependent subthreshold resonance in the theta frequency range (4–12 Hz). Another inhibitory subtype in the MOB, the periglomerular cells, exhibited Ih-dependent subthreshold resonance in the delta range (1–4 Hz), while principal neurons, the mitral cells, do not exhibit Ih-dependent subthreshold resonance. Importantly, Ih size, as well as the strength and frequency of resonance in GCs, exhibited a postnatal developmental progression, suggesting that this development of Ih in GCs may differentially contribute to their integration of sensory input and contribution to oscillatory circuit dynamics.