D'Angelo E, Schieppati M
Respir Physiol. 1982 Nov;50(2):221-38. doi: 10.1016/0034-5687(82)90020-2.
The relationship between relative peak activity (moving average EMG) of the diaphragm (Adi) and of the cranial (2nd and 3rd) external intercostal or parasternal muscles (Aic) was assessed during rebreathing in animals before and after bilateral thoracic (T1-T4) dorsal rhizotomy (TDR) and/or bilateral vagotomy (VGT). The relationship had the form Aic=a Adib under all conditions. In intact rabbits and cats mean values for b were 1.48 and 1.79, respectively, a being unity by definition. Neither TDR nor VGT changed b; a decreased to about 0.15 with TDR and halved with VGT only if performed before TDR. Selective reflex facilitation of inspiratory intercostals with occlusions at FRC was observed after VGT and was abolished by TDR. Neither VGT nor TDR affected Adi time course. Hence: (1) central command to alpha-motoneurones of the major inspiratory muscles differs; (2) proprioceptive feedback markedly increases external intercostal activity, apparently by multiplying Aic due to central command to alpha-motoneurones by a factor independent of chemical drive; (3) vagally mediated augmentation of Aic depends entirely on intact proprioceptive feedback. The possible role of fusimotor drive is discussed.
在双侧胸段（T1 - T4）背根切断术（TDR）和/或双侧迷走神经切断术（VGT）前后，对动物在重复呼吸过程中膈肌（Adi）与胸廓上部（第2和第3肋间）或胸骨旁肌（Aic）的相对峰值活动（移动平均肌电图）之间的关系进行了评估。在所有情况下，这种关系的形式均为Aic = aAdib。在完整的兔子和猫中，b的平均值分别为1.48和1.79，根据定义a为1。TDR和VGT均未改变b；仅在TDR之前进行VGT时，TDR会使a降至约0.15，而VGT会使其减半。VGT后观察到在功能残气量（FRC）时吸气性肋间肌的选择性反射增强，而TDR可消除这种增强。VGT和TDR均未影响Adi的时间进程。因此：（1）对主要吸气肌的α运动神经元的中枢指令不同；（2）本体感受反馈明显增加了肋间外肌的活动，显然是通过将α运动神经元的中枢指令导致的Aic乘以一个与化学驱动无关的因子；（3）迷走神经介导的Aic增强完全依赖于完整的本体感受反馈。文中讨论了肌梭运动驱动的可能作用。
