Patterns of expiratory and inspiratory activation for thoracic motoneurones in the anaesthetized and the decerebrate rat
Patterns of expiratory and inspiratory activation for thoracic motoneurones in the anaesthetized and the decerebrate rat
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DOI：
10.1113/jphysiol.2010.192518
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发表时间：
2010-08-01
影响因子：
5.5
通讯作者：
Kirkwood, Peter A.
中科院分区：
文献类型：
--
作者：
de Almeida, Anoushka T. R.;Al-Izki, Sarah;Kirkwood, Peter A.
对吐气肌的神经控制，特别是对大鼠的神经控制，还不如对吸气肌的神经控制了解得多。因此，研究了成年大鼠在高碳酸血症和麻醉或失觉情况下，尾端肋间隙肌肉的呼吸放电模式。在神经肌肉阻滞和人工通气的情况下，肋间外神经和肋间内神经均出现吸气和呼气的传出放电。对于仅支配肋间肌和肋下肌的近端肋间神经分支也是如此。如果活动，其他物种的这一肌肉区域总是呼气。在这里，吸气爆发几乎总是存在的。当麻醉减轻或前去觉麻醉逐渐消失时，呼气活动才逐渐和间歇性地出现。间歇性的出现被解释为缓慢的髓质呼气振荡器与快速的吸气振荡器的耦合。神经放电的模式，特别是内部和肋下层的吸气或双相激活，通过观察自发呼吸准备中的等效肌电图放电模式得到证实，使用去神经支配程序来识别哪些肌肉产生了信号。一些运动单位在吸气和呼气爆发中都被调动起来。这些活动模式以前没有被描述过，并且对成人多个呼吸振荡器的功能作用和尾侧肋间隙肌肉的机械作用都有影响，包括肋下肌，这是一个部分半节段肌。
The nervous control of expiratory muscles is less well understood than that of the inspiratory muscles, particularly in the rat. The patterns of respiratory discharges in adult rats were therefore investigated for the muscles of the caudal intercostal spaces, with hypercapnia and under either anaesthesia or decerebration. With neuromuscular blockade and artificial ventilation, efferent discharges were present for both inspiration and expiration in both external and internal intercostal nerves. This was also the case for proximal internal intercostal nerve branches that innervate only internal intercostal and subcostalis muscles. If active, this region of muscle in other species is always expiratory. Here, inspiratory bursts were almost always present. The expiratory activity appeared only gradually and intermittently, when the anaesthesia was allowed to lighten or as the pre-decerebration anaesthesia wore off. The intermittent appearance is interpreted as the coupling of a slow medullary expiratory oscillator with a faster inspiratory one. The patterns of nerve discharges, in particular the inspiratory or biphasic activation of the internal and subcostalis layers, were confirmed by observations of equivalent patterns of EMG discharges in spontaneously breathing preparations, using denervation procedures to identify which muscles generated the signals. Some motor units were recruited in both inspiratory and expiratory bursts. These patterns of activity have not previously been described and have implications both for the functional role of multiple respiratory oscillators in the adult and for the mechanical actions of the muscles of the caudal intercostal spaces, including subcostalis, which is a partly bisegmental muscle.