Department of Physiology & Perinatal Research Centre, Faculty of Medicine & Dentistry, Heritage Medical Research Centre, University of Alberta, Edmonton, Canada.
Respir Physiol Neurobiol. 2011 Jan 31;175(1):37-48. doi: 10.1016/j.resp.2010.09.004. Epub 2010 Sep 15.
Recently developed transversal newborn rat brainstem slices with "calibrated" rostrocaudal margins unraveled novel features of rhythmogenic inspiratory active pre-Bötzinger complex (preBötC) neural networks (Ballanyi and Ruangkittisakul, 2009). For example, slice rhythm in physiological (3 mM) superfusate K(+) is depressed by modestly raised Ca²(+) and restored by raised K(+). Correspondingly, we generated here calibrated preBötC slices from commonly used newborn C57BL/6 mice in which rostrocaudal extents of respiratory marker structures, e.g., the inferior olive, turned out to be smaller than in newborn rats. Slices of 400-600 μm thickness with likely centered preBötC kernel ("m-preBötC slices") generated rhythm in 3 mM K(+) and 1mM Ca(2+) for several hours although its rate decreased to < 5 bursts/min after >1 h. Rhythm was stable at 8-12 bursts/min in 6-7 mM K(+), depressed by 2 mM Ca²(+), and restored by 9 mM K(+). Our findings provide the basis for future structure-function analyses of the mouse preBötC, whose activity depends critically on a "Ca(+)/K(+) antagonism" as in rats.
最近开发的具有“校准”头尾边界的新生大鼠脑桥切片揭示了呼吸节律性吸气前 Bötzinger 复合体（preBötC）神经网络的新特征（Ballanyi 和 Ruangkittisakul，2009 年）。例如，在生理（3mM）灌流液 K+中，切片节律会被适度升高的 Ca²+抑制，并被升高的 K+恢复。相应地，我们从常用的新生 C57BL/6 小鼠中生成了校准的 preBötC 切片，其中呼吸标记结构（例如下橄榄）的头尾范围比新生大鼠小。厚度为 400-600μm 的切片，可能位于 preBötC 核心区域（“m-preBötC 切片”），在 3mM K+和 1mM Ca(2+)中可以产生数小时的节律，尽管在 1 小时后其频率降低到<5 次/分钟。在 6-7mM K+中，节律稳定在 8-12 次/分钟，被 2mM Ca²+抑制，被 9mM K+恢复。我们的发现为未来对小鼠 preBötC 的结构-功能分析提供了基础，其活动取决于与大鼠相似的“Ca(+)/K(+)拮抗作用”。
