Beth Zimmer M, Grant Joshua S, Ayar Angelo E, Goshgarian Harry G
J Spinal Cord Med. 2015 Mar;38(2):224-30. doi: 10.1179/2045772314Y.0000000220. Epub 2014 Jun 26.
Upper cervical spinal cord hemisection causes paralysis of the ipsilateral hemidiaphragm; however, the effect of C2 hemisection on the function of the intercostal muscles is not clear. We hypothesized that C2 hemisection would eliminate inspiratory intercostal activity ipsilateral to the injury and that some activity would return in a time-dependent manner.
Female Sprague Dawley rats were anesthetized with urethane and inspiratory intercostal electromyogram (EMG) activity was recorded in control rats, acutely injured C2 hemisected rats, and at 1 and 16 weeks post C2 hemisection.
Bilateral recordings of intercostal EMG activity showed that inspiratory activity was reduced immediately after injury and increased over time. EMG activity was observed first in rostral spaces followed by recovery occurring in caudal spaces. Theophylline increased respiratory drive and increased intercostal activity, inducing activity that was previously absent.
These results suggest that there are crossed, initially latent, respiratory connections to neurons innervating the intercostal muscles similar to those innervating phrenic motor neurons.
上颈段脊髓半切会导致同侧半膈肌麻痹；然而，C2半切对肋间肌功能的影响尚不清楚。我们假设C2半切会消除损伤同侧的吸气性肋间活动，并且一些活动会随时间推移而恢复。
用乌拉坦麻醉雌性Sprague Dawley大鼠，记录对照大鼠、急性损伤的C2半切大鼠以及C2半切后1周和16周时的吸气性肋间肌肌电图（EMG）活动。
肋间肌EMG活动的双侧记录显示，损伤后吸气活动立即减少，并随时间增加。EMG活动首先在头侧间隙观察到，随后在尾侧间隙恢复。茶碱增加呼吸驱动并增加肋间活动，诱导出先前不存在的活动。
这些结果表明，存在与支配肋间肌的神经元交叉的、最初潜伏的呼吸连接，类似于支配膈运动神经元的连接。
