Optogenetic excitation of preBotzinger complex neurons potently drives inspiratory activity in vivo
Optogenetic excitation of preBotzinger complex neurons potently drives inspiratory activity in vivo
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DOI：
10.1113/jp270471
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发表时间：
2015-08-15
影响因子：
5.5
通讯作者：
Pagliardini, Silvia
中科院分区：
文献类型：
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作者：
Alsahafi, Zaki;Dickson, Clayton T.;Pagliardini, Silvia
了解呼吸节律发生的部位和机制是呼吸神经生理学领域的基本兴趣。以往的研究表明，在体外和体内的必要和充分的作用，前Botzinger复合体（preBotC）在产生吸气节律。然而，鉴于先前使用的实验方法，体内preBotC网络的定时激活的影响是未知的。通过使用表达通道视紫红质的腺相关病毒单方面感染preBotC神经元，我们光激活了网络，以评估以空间和时间精确的方式传递到吸气振荡器的兴奋如何影响持续的呼吸节律和相关的肌肉活动在麻醉大鼠中。我们假设，如果兴奋性驱动对于节律发生和爆发启动是必要的，那么preBotC的光激活不仅会增加呼吸频率，而且会在快速启动的宽频率范围内携带它，并且如果在吸气期间提供刺激，对持续的呼吸节律影响很小。preBotC神经元的刺激一致地增加呼吸率和夹带呼吸高达四倍的基线条件。此外，在吸气事件之间的随机相位处递送的光刺激的短暂脉冲稳健且一致地诱导相位无关性（0型）呼吸重置，并在非常短的延迟（约100ms）下募集吸气肌活动。还确定了吸气后200 ms的不应期。这些数据为preBotC中吸气活动的精细控制提供了强有力的证据，并提供了preBotC网络构成吸气节律的基本振荡器的进一步证据。
Understanding the sites and mechanisms underlying respiratory rhythmogenesis is of fundamental interest in the field of respiratory neurophysiology. Previous studies demonstrated the necessary and sufficient role of preBotzinger complex (preBotC) in generating inspiratory rhythms in vitro and in vivo. However, the influence of timed activation of the preBotC network in vivo is as yet unknown given the experimental approaches previously used. By unilaterally infecting preBotC neurons using an adeno-associated virus expressing channelrhodopsin we photo-activated the network in order to assess how excitation delivered in a spatially and temporally precise manner to the inspiratory oscillator influences ongoing breathing rhythms and related muscular activity in urethane-anaesthetized rats. We hypothesized that if an excitatory drive is necessary for rhythmogenesis and burst initiation, photo-activation of preBotC not only will increase respiratory rate, but also entrain it over a wide range of frequencies with fast onset, and have little effect on ongoing respiratory rhythm if a stimulus is delivered during inspiration. Stimulation of preBotC neurons consistently increased respiratory rate and entrained respiration up to fourfold baseline conditions. Furthermore, brief pulses of photostimulation delivered at random phases between inspiratory events robustly and consistently induced phase-independent (Type 0) respiratory reset and recruited inspiratory muscle activity at very short delays (approximate to 100ms). A 200ms refractory period following inspiration was also identified. These data provide strong evidence for a fine control of inspiratory activity in the preBotC and provide further evidence that the preBotC network constitutes the fundamental oscillator of inspiratory rhythms.