Palisses R, Persegol L, Viala D, Viala G
Laboratorie de Neurophysiologie, UA CNRS 1199, Faculté des Sciences Mirande, Dijon, France.
Neuroscience. 1988 Feb;24(2):719-28. doi: 10.1016/0306-4522(88)90364-8.
The neurogenic effect of passive hindlimb movement on phrenic nerve discharge was compared in decorticate unanaesthetized and curarized rabbit preparations prior to and after spinal transection. The question of how and where sensory information has access to the central respiratory network was addressed in each case. All passive motions, performed using a mechanical device, were of constant amplitude in a given preparation. The results clearly differed in decorticate and spinal preparations. In the decorticate vagotomized preparation, periodic passive motions led to an immediate shortening of the respiratory period which lasted throughout the periodic stimulation and stopped with its cessation; it did not depend on the frequency of the natural stimulation and was entirely due to a 20% shortening of the expiration time. Maintained full flexion or full extension both induced the same expiration time shortening, but limited to the first two to three respiratory cycles after onset and interruption of stimulation. After spinal transection at the C2 level, and moderate activation with DOPA, no phrenic activity developed in the absence of proprioceptive stimulation. Periodic hindlimb movements evoked simultaneous large bursts in both phrenic nerves during each extension; a 1:1 coordination of phrenic activity with the external imposed period (P) was observed for various P values. A strong phrenic activation could also be elicited through maintained full hindlimb extension but not through full flexion: this activation appeared as rhythmic discharge as long as extension was maintained. It is concluded that proprioceptive inputs act upon the medullary respiration generator and reset its own rhythm whereas, at the spinal level, they elicit an amplitude modulation at phrenic motoneuronal level without acting upon the rate of the spinal "respiration" generator itself; on the same phrenic motoneurons, a subthreshold central activation added to a subthreshold proprioceptive activation probably accounts for the phrenic bursting during maintained extension. Finally, the proprioceptive control from the hindlimb on phrenic activity is processed at different sites of the central respiratory network at medullary and at spinal level, and may depend on different input signals.
在脊髓横断前后，对去皮质未麻醉且箭毒化的兔制备物中被动后肢运动对膈神经放电的神经源性效应进行了比较。在每种情况下，都探讨了感觉信息如何以及在何处进入中枢呼吸网络的问题。所有使用机械设备进行的被动运动，在给定的制备物中幅度恒定。去皮质和脊髓制备物的结果明显不同。在去皮质迷走神经切断的制备物中，周期性被动运动导致呼吸周期立即缩短，这种缩短在整个周期性刺激过程中持续，并随着刺激停止而停止；它不依赖于自然刺激的频率，完全是由于呼气时间缩短了20%。持续的完全屈曲或完全伸展都导致相同的呼气时间缩短，但仅限于刺激开始和中断后的前两到三个呼吸周期。在C2水平进行脊髓横断并使用多巴进行适度激活后，在没有本体感受刺激的情况下，没有出现膈神经活动。周期性后肢运动在每次伸展时引起双侧膈神经同时出现大的爆发；对于不同的P值，观察到膈神经活动与外部施加周期（P）的1:1协调。通过持续的后肢完全伸展也可以引发强烈的膈神经激活，但通过完全屈曲则不能：只要保持伸展，这种激活就表现为节律性放电。得出的结论是，本体感受输入作用于延髓呼吸发生器并重置其自身节律，而在脊髓水平，它们在膈运动神经元水平引发幅度调制，而不作用于脊髓“呼吸”发生器本身的速率；在同一膈运动神经元上，阈下中枢激活加上阈下本体感受激活可能是维持伸展期间膈神经爆发的原因。最后，后肢对膈神经活动的本体感受控制在延髓和脊髓水平的中枢呼吸网络的不同部位进行处理，并且可能依赖于不同的输入信号。
