The canine phrenic-to-intercostal reflex
The canine phrenic-to-intercostal reflex
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DOI：
10.1111/j.1469-7793.1998.919bp.x
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发表时间：
1998-05-01
影响因子：
5.5
通讯作者：
De Troyer, A
中科院分区：
文献类型：
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作者：
De Troyer, A
1.狗的横膈膜麻痹引起吸气肋间肌活动的非迷走神经性、非化学性增加。在本研究中，这一假设被验证，膈传入纤维可能会引起吸气肋间活动的反射抑制。在20只切断迷走神经的自主呼吸犬上，记录吸气时三组肋间肌（胸骨旁肋间肌、肋间外肌和肋提肌）的电活动，并在吸气时刺激一侧或双侧C5膈神经根近端.刺激同侧和对侧C5膈神经根引起吸气性肋间活动立即减少。切断C5后根后重复刺激膈神经可消除这种降低。当刺激强度为运动阈值的3倍时，双侧C5传入刺激时，肋间肌和肋提肌的外肌活动减少，当刺激强度进一步增加时，其幅度增加。相比之下，胸骨旁肋间活动的减少仅发生在刺激强度为运动阈值的12倍时。这些观察结果证实了这一假设，即交感神经受体可能反射性抑制传出活动的吸气肋间肌，特别是外肋间肌和肋提肌。这种抑制作用似乎主要由小的有髓纤维介导。
1. Paralysis of the diaphragm in the dog causes a non-vagal, non-chemical increase in the activity of the inspiratory intercostal muscles. In the present studies, the hypothesis was tested that phrenic afferent fibres may elicit a reflex inhibition of inspiratory intercostal activity.2. The electrical activity of the three groups of inspiratory intercostal muscles (parasternal intercostals, external intercostals, levator costae) was recorded in twenty vagotomized, spontaneously breathing dogs, and the proximal end of one or both C5 phrenic nerve roots was stimulated during inspiration.3. Stimulation of the ipsilateral and contralateral C5 phrenic roots caused an immediate reduction in inspiratory intercostal activity. This reduction was abolished when phrenic stimulation was repeated after section of the C5 dorsal roots.4. The reduction in external intercostal and levator costae activity during bilateral C5 afferent stimulation appeared when the stimulus strength was 3 times the motor threshold and it increased in magnitude when stimulus intensity was increased further. In contrast, the reduction in parasternal intercostal activity occurred only when the stimulus strength was 12 times the motor threshold.5. These observations confirm the hypothesis that diaphragmatic receptors may reflexly inhibit efferent activity to the inspiratory intercostal muscles, in particular the external intercostals and levator costae. This inhibition appears to be primarily mediated by small myelinated fibres.