Emergence of intrinsic bursting in trigeminal sensory neurons parallels the acquisition of mastication in weanling rats
Emergence of intrinsic bursting in trigeminal sensory neurons parallels the acquisition of mastication in weanling rats
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DOI：
10.1152/jn.00352.2006
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发表时间：
2006-11-01
影响因子：
2.5
通讯作者：
Kolta, Arlette
中科院分区：
文献类型：
--
作者：
Brocard, Frederic;Verdier, Dorly;Kolta, Arlette
越来越多的证据表明，三叉神经背侧主感觉核中的神经元亚群不是简单的丘脑感觉中继，而是可能形成负责咀嚼的中枢模式产生回路的核心。在本文中，我们使用全细胞补丁记录在年轻大鼠的脑干切片，这些神经元具有内在的爆发能力，坚持在细胞外Ca 2+的情况下。应用不同的K+通道阻滞剂影响爆发的持续时间和放电频率，但保持爆发能力不变。爆发是电压依赖性的，并取消了低浓度的Na+通道阻滞剂。爆裂神经元的比例显着增加，在出生后第二周，在平行的几个电生理特性的深刻变化。这是咀嚼运动出现和成熟的时期。爆发与发展的后去极化，依赖于成熟的持久性钠电导（I-NaP）。一个有趣的发现是，爆发的发生和I-NaP的大小都受到胞外Ca ~（2+）浓度的调节。降低细胞外[Ca ~（2+）]增加I-NaP和爆裂的可能性。我们认为，这些机制的基础上爆发代咀嚼和类似的过程可能会发现在其他电机模式发电机。
There is increasing evidence that a subpopulation of neurons in the dorsal principal sensory trigeminal nucleus are not simple sensory relays to the thalamus but may form the core of the central pattern generating circuits responsible for mastication. In this paper, we used whole cell patch recordings in brain stem slices of young rats to show that these neurons have intrinsic bursting abilities that persist in absence of extracellular Ca2+. Application of different K+ channel blockers affected duration and firing rate of bursts, but left bursting ability intact. Bursting was voltage dependent and was abolished by low concentrations of Na+ channel blockers. The proportion of bursting neurons increased dramatically in the second postnatal week, in parallel with profound changes in several electrophysiological properties. This is the period in which masticatory movements appear and mature. Bursting was associated with the development of an afterdepolarization that depend on maturation of a persistent sodium conductance (I-NaP). An interesting finding was that the occurrence of bursting and the magnitude of I-NaP were both modulated by the extracellular concentration of Ca2+. Lowering extracellular [Ca2+] increased both I-NaP and probability of bursting. We suggest that these mechanisms underlie burst generation in mastication and that similar processes may be found in other motor pattern generators.