Postnatal development of dendrodendritic inhibition in the Mammalian olfactory bulb.
Postnatal development of dendrodendritic inhibition in the Mammalian olfactory bulb.
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DOI：
10.3389/fncel.2011.00010
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发表时间：
2011
影响因子：
5.3
通讯作者：
Murthy VN
中科院分区：
文献类型：
--
作者：
Dietz SB;Markopoulos F;Murthy VN
线粒体-颗粒细胞（mitral-granule cell，MC-GC）相互突触是嗅球（olfactory bulb，OB）中自抑制和侧抑制的重要来源，这种局部抑制对气味辨别至关重要。通过将MC自抑制功能的发育与嗅觉功能的生后发育相联系，我们可以更深入地了解MC自抑制在嗅觉中的作用。我们研究了功能的发展，MC-GC相互突触使用全细胞膜片钳记录从MC和GC在急性OB切片从3日龄至30日龄的大鼠。通过对单个MC去极化并记录同一细胞中的复发性抑制来测量的树突状抑制（DDI）的幅度增加至生命的第15天（P15），但在P15和P30之间下降。DDI的最初增加和后来的减少与微型抑制性突触后电流频率的类似增加和减少相呼应，这表明可用于参与DDI的突触数量的伴随调制。DDI的晚期降低也可能部分归因于GC兴奋性的降低以及N-甲基d-天冬氨酸（NMDA）受体对GC突触释放γ-氨基丁酸（GABA）的相对贡献的增加。GABA能突触释放概率的变化不太可能解释DDI的晚期减少，尽管它们可能有助于发育过程中DDI的早期增加。我们的研究结果表明，功能MC-GC电路的发展，在一个复杂的方式，可能包括建设和消除突触。
The mitral–granule cell (MC–GC) reciprocal synapse is an important source of auto- and lateral-inhibition in the olfactory bulb (OB), and this local inhibition is critical for odor discrimination. We may gain insight into the role of MC autoinhibition in olfaction by correlating the functional development of the autoinhibition with the postnatal development of olfactory function. We have studied the functional development of the MC–GC reciprocal synapse using whole-cell patch-clamp recordings from MCs and GCs in acute OB slices from 3- to 30-day-old rats. The magnitude of dendrodendritic inhibition (DDI) measured by depolarizing a single MC and recording recurrent inhibition in the same cell increased up to the fifteenth day of life (P15), but dropped between P15 and P30. The initial increase and later decrease in DDI was echoed by a similar increase and decrease in the frequency of miniature inhibitory post-synaptic currents, suggesting an accompanying modulation in the number of synapses available to participate in DDI. The late decrease in DDI could also result, in part, from a decrease in GC excitability as well as an increase in relative contribution of N-methyl d-aspartate (NMDA) receptors to γ-amino butyric acid (GABA) release from GC synapses. Changes in release probability of GABAergic synapses are unlikely to account for the late reduction in DDI, although they might contribute to the early increase during development. Our results demonstrate that the functional MC–GC circuit evolves over development in a complex manner that may include both construction and elimination of synapses.